Free Online Calculators for Everything
Fast, accurate calculators for finance, math, health, currency conversion, cricket, and football — with live exchange rates, interactive charts, and step-by-step results. Free, mobile-friendly, and no sign-up required.
Scientific Calculator
Trig · logs · powers · roots · factorial · memory — all in one
Memory: 0 · Mode: DEG · Tap 2nd for inverse trig, x!, 1/x, π, e & more.
Open full-screen version with graphingCurrency
Financial
Financial → Personal Finance
Loan Calculator
Calculate monthly loan payments, total interest, and payoff time.
Interest Calculator
Calculate simple interest on a principal amount over time.
Compound Interest Calculator
Calculate compound interest growth with custom compounding frequency.
Inflation Calculator
See how inflation erodes purchasing power and increases future costs over time.
Budget Calculator
Plan a monthly budget across income, expenses, and savings.
50/30/20 Rule Calculator
Split your take-home pay into needs, wants, and savings using the 50/30/20 rule.
70/20/10 Rule Money Calculator
Divide your income into spending, savings, and debt repayment buckets.
Savings Calculator
See how your savings grow over time with regular deposits and interest.
Savings Goal Calculator
Find out how much to save each month to hit a target savings goal.
Savings Plan Calculator
Build a month-by-month savings plan to reach a future goal amount.
Auto Loan Calculator
Estimate your monthly car loan payment, total interest, and payoff schedule.
Car Affordability Calculator
Find out how much car you can afford based on your income and budget.
Car Depreciation Calculator
Estimate how much a car's value drops each year of ownership.
Boat Loan Calculator
Calculate monthly payments and total cost for a boat loan.
403(b) Calculator
Project the future value of your 403(b) retirement contributions.
529 Calculator
Project how a 529 education savings plan grows over time.
Sabbatical Calculator
Work out how much you need to save to fund a career break.
Bank Reconciliation Calculator
Reconcile your book balance against your bank statement balance.
Scrap Gold Calculator
Estimate the melt value of scrap gold by weight and purity.
Scrap Silver Calculator
Estimate the melt value of scrap silver by weight and purity.
Silver Melt Calculator
Calculate the melt value of silver coins and bars at current spot price.
APC Calculator
Calculate the Average Propensity to Consume from income and spending.
Financial → Tax & Salary
Income Tax Calculator
Estimate your income tax liability based on slab rates.
Income Tax / TDS Estimator
Apply Section 80C, 80D, HRA, and other deductions to compare tax under Old vs New regime.
CTC Calculator
Break your CTC into Basic, HRA, PF, and gratuity to find your in-hand salary.
Gratuity Calculator
Calculate your final gratuity payout based on years of service and last drawn salary.
In-Hand Salary / Take-Home Calculator
Deduct PF, gratuity, professional tax, and estimated TDS to find your exact monthly salary.
GST Calculator
Add or remove GST from any amount with a full CGST, SGST, and IGST breakup.
Salary Calculator
Convert your pay between hourly, daily, weekly, monthly, and annual amounts.
Sales Tax Calculator
Calculate sales tax added to a price, or extract tax from a tax-included total.
Adjusted Gross Income (AGI) Calculator
Calculate your Adjusted Gross Income from total income and eligible deductions.
Modified Adjusted Gross Income (MAGI) Calculator
Calculate your Modified Adjusted Gross Income for tax and eligibility purposes.
AMT Calculator
Estimate your liability under the Alternative Minimum Tax.
Annual Income Calculator
Convert hourly, daily, or monthly pay into an annual income figure.
Net to Gross Calculator
Work backward from a take-home amount to the equivalent gross salary.
Pay Raise Calculator
Calculate your new salary and percentage increase after a pay raise.
Prorated Salary Calculator
Calculate a prorated salary for a partial pay period.
Overtime Calculator
Calculate overtime pay based on your regular hourly rate and hours worked.
12-Hour Shift Pay Calculator
Calculate total pay for 12-hour shift schedules, including overtime.
Billable Hours Calculator
Calculate billable hours and revenue from tracked work time.
Bill Rate Calculator
Work out the hourly bill rate needed to hit a target revenue or salary.
Mileage Reimbursement Calculator
Calculate mileage reimbursement owed based on distance driven and rate per mile.
Lottery Tax Calculator
Estimate the tax withheld and take-home amount from lottery winnings.
Financial → Mortgage & Real Estate
Mortgage Calculator
Calculate your monthly mortgage payment and amortization schedule.
Amortization Calculator
See a full year-by-year loan amortization schedule with principal vs interest.
Home Loan EMI Calculator (India)
Calculate your home loan EMI and compare rates across SBI, HDFC, ICICI, Bank of Baroda and PNB.
SBI Home Loan Calculator
Calculate your SBI home loan EMI and compare it against other top Indian banks.
HDFC Home Loan Calculator
Calculate your HDFC Bank home loan EMI and compare it against other top Indian banks.
ICICI Home Loan Calculator
Calculate your ICICI Bank home loan EMI and compare it against other top Indian banks.
Bank of Baroda Home Loan Calculator
Calculate your Bank of Baroda home loan EMI and compare it against other top Indian banks.
PNB Home Loan Calculator
Calculate your Punjab National Bank home loan EMI and compare it against other top Indian banks.
Mortgage Amortization Calculator
Break down a mortgage's principal and interest payments across every year of the loan.
ARM Mortgage Calculator
Estimate payments on an adjustable-rate mortgage across its fixed and floating periods.
Biweekly Mortgage Calculator
See how switching to biweekly mortgage payments shortens your loan term.
Bi-Weekly Mortgage Payment Calculator
Calculate the exact payment amount and schedule for a biweekly mortgage.
Mortgage Payoff Calculator
See how extra payments shorten your mortgage payoff timeline and save interest.
Mortgage Refinance Calculator
Compare your current mortgage against a refinance offer to see potential savings.
Mortgage Rate Calculator
Estimate the mortgage interest rate you might qualify for.
Mortgage Points Calculator
See whether paying for mortgage points is worth it based on your breakeven point.
Mortgage Prepayment Calculator
Calculate the interest and time saved by prepaying part of your mortgage.
Mortgage Penalty Calculator
Estimate the prepayment penalty for paying off a mortgage early.
Cap Rate Calculator
Calculate a property's capitalization rate from net operating income and value.
Net Operating Income Calculator
Calculate a rental property's net operating income from revenue and expenses.
Occupancy Rate Calculator
Calculate the occupancy rate of a rental property or portfolio.
Commercial Lease Calculator
Estimate monthly and total costs for a commercial lease agreement.
Net Effective Rent Calculator
Calculate net effective rent after accounting for free-rent concessions.
3x Rent Calculator
Check the minimum income typically required to qualify for a rental at 3x the rent.
ARV Calculator
Estimate a property's After Repair Value for house-flipping and renovation deals.
AFFO Calculator
Calculate Adjusted Funds From Operations for REIT and real estate analysis.
ADR Calculator
Calculate the Average Daily Rate for a hotel or short-term rental property.
Financial → Equity & Investment
Investment Calculator
Project the future value of a lump sum plus recurring monthly investments.
Beta Stock Calculator
Calculate a stock's beta to measure its volatility relative to the market.
Portfolio Beta Calculator
Calculate the weighted beta of an entire investment portfolio.
NAV Calculator
Calculate mutual fund NAV, portfolio net asset value, per-unit NAV, and premium or discount.
CAPM Calculator
Estimate a stock's expected return using the Capital Asset Pricing Model.
Cost of Equity Calculator
Calculate the cost of equity using CAPM or the dividend growth model.
Cost of Capital Calculator
Calculate a company's weighted average cost of capital (WACC).
Carried Interest Calculator
Calculate a fund manager's carried interest share of investment profits.
Dividend Calculator
Project future dividend income from your share holdings and reinvestment.
Dividend Yield Calculator
Calculate a stock's dividend yield from its price and annual dividend.
Dividend Payout Ratio Calculator
Calculate what share of earnings a company pays out as dividends.
Dividend Discount Model Calculator
Estimate a stock's intrinsic value using the Dividend Discount Model.
DuPont Analysis Calculator
Break down Return on Equity into margin, turnover, and leverage components.
Residual Income Calculator
Calculate residual income after covering the cost of invested capital.
Operating Cash Flow Ratio Calculator
Measure a company's ability to cover liabilities using operating cash flow.
PEG Ratio Calculator
Calculate the Price/Earnings-to-Growth ratio to gauge valuation against growth.
Price to Earnings Ratio Calculator
Calculate a stock's P/E ratio from its price and earnings per share.
Price to Book Ratio Calculator
Calculate a stock's Price-to-Book ratio from market price and book value.
Price to Cash Flow Ratio Calculator
Calculate a stock's Price-to-Cash-Flow ratio for valuation analysis.
Price to Sales Ratio Calculator
Calculate a stock's Price-to-Sales ratio from market cap and revenue.
Financial → Retirement
Retirement Calculator
Project your retirement savings balance based on contributions and expected returns.
401(k) Calculator
Project your 401(k) balance at retirement based on contributions and employer match.
IRA Calculator
Project the growth of a Traditional IRA and its tax-deferred contributions.
Roth IRA Calculator
Project the tax-free growth of a Roth IRA over time.
Early Retirement Calculator
Find out how much you need to save to retire earlier than the usual age.
Retirement Withdrawal Calculator
Plan a sustainable withdrawal rate from your retirement savings.
Savings Withdrawal Calculator
See how long your savings will last at a given withdrawal rate.
Rule of 72 Calculator
Quickly estimate how long it takes an investment to double at a given rate.
Annuity Calculator
Calculate the future value of a fixed annuity from regular contributions.
Annuity Payout Calculator
Calculate the periodic payout from an annuity over a set term.
Immediate Annuity Calculator
Calculate income payments from an annuity that starts paying out right away.
Deferred Annuity Calculator
Calculate the growth of an annuity during its deferral period before payout.
Variable Annuity Calculator
Project annuity value when returns vary with underlying investment performance.
Growing Annuity Calculator
Calculate the present value of an annuity with payments that grow over time.
Future Value of Annuity Calculator
Calculate the future value of a series of equal periodic payments.
Present Value of Annuity Calculator
Calculate the present value of a series of future equal payments.
Financial → Trading & Markets
Financial → Trading & Markets → Day Trading
Position Size Calculator
Work out the exact share quantity or lot size to trade from your capital and risk percentage.
Risk-to-Reward (R2R) Calculator
Calculate the risk-to-reward ratio for a trade from your entry, stop-loss, and target, with a live stock price lookup.
Brokerage & Net P&L Calculator
Deduct brokerage, STT, GST, and stamp duty from gross profit to find your net P&L.
Average Down / Multi-Entry Calculator
Find your new average entry price across multiple buy orders.
Financial → Trading & Markets → Options & F&O
Option Delta / Target Price Calculator
Estimate the expected option premium for a given spot or index target.
Option Premium R2R Calculator
Calculate total max profit and max loss from entry premium, stop-loss, target, and lot size.
Option Greeks Calculator (Black-Scholes)
Calculate Delta, Theta, Vega, and Gamma from implied volatility and days to expiry.
Options Payoff & Breakeven Calculator
Plot the payoff graph and breakeven points for a multi-leg options strategy.
Financial → Trading & Markets → Investment & Wealth
SIP Return Calculator
Estimate mutual fund SIP maturity value, step-up SIP growth, tax impact, and inflation-adjusted returns.
SWP Calculator
Track your corpus balance over time with a systematic withdrawal plan.
FIRE / Early Retirement Calculator
Work out the retirement corpus you need based on current expenses and inflation.
Financial → Trading & Markets → Technicals & Advanced Risk
Pivot Points & CPR Calculator
Calculate the daily CPR and pivot levels S1-S4, R1-R4 from the high, low, and close.
Fibonacci Level Calculator
Find retracement and extension levels from a swing high and swing low.
Crypto Futures Liquidation Calculator
Estimate your liquidation price from entry price and leverage (5x-20x).
Risk of Ruin Calculator
Estimate the probability of blowing up your account from your win rate and R2R ratio.
Health & Fitness
Health & Fitness → BMI Calculators
BMI Calculator
Calculate your Body Mass Index and see your healthy weight range.
BMI Calculator for Men
Calculate BMI with healthy weight ranges tailored for men.
BMI Calculator for Women
Calculate BMI with healthy weight ranges tailored for women.
BMI Calculator for Kids
Calculate BMI-for-age percentile for children using CDC growth charts.
BMI Calculator for Teens
Calculate BMI-for-age percentile for teenagers.
Geriatric BMI Calculator
Calculate BMI with healthy ranges adjusted for older adults.
BMI Weight Loss Calculator
See how much weight to lose to reach a target BMI.
Overweight Calculator
Check how far your weight is from a healthy range for your height.
Health & Fitness → Body Measurements
Body Fat Calculator
Estimate your body fat percentage using the U.S. Navy circumference method.
Ideal Weight Calculator
Estimate your ideal body weight using several standard medical formulas.
Lean Body Mass Calculator
Calculate the weight of everything in your body except fat mass.
ABSI Calculator
Calculate A Body Shape Index from waist circumference, height, and weight.
BAI Calculator
Estimate body fat percentage using the Body Adiposity Index from hip and height.
BRI Calculator
Calculate the Body Roundness Index from waist circumference and height.
BSA Calculator
Calculate Body Surface Area from height and weight for clinical dosing.
Adjusted Body Weight Calculator
Calculate adjusted body weight for dosing in overweight or obese patients.
Overweight Calculator
Check how far your weight is from a healthy range for your height.
Body Frame Size Calculator
Determine your body frame size (small, medium, large) from wrist circumference.
Body Shape Calculator
Determine your body shape from bust, waist, and hip measurements.
Waist to Hip Ratio Calculator
Calculate your waist-to-hip ratio to assess health risk.
Waist to Height Ratio Calculator
Calculate your waist-to-height ratio, a simple indicator of health risk.
FFMI Calculator
Calculate your Fat-Free Mass Index to assess muscularity relative to height.
RFM Calculator
Estimate body fat percentage using the Relative Fat Mass formula.
Skinfold Body Fat Calculator
Estimate body fat percentage from skinfold caliper measurements.
Ponderal Index Calculator
Calculate the Ponderal Index, an alternative to BMI that scales with height cubed.
Karvonen Formula Calculator
Calculate your target heart rate training zones using the Karvonen formula.
Face Shape Calculator
Determine your face shape from facial measurements.
Draw Length Calculator
Calculate the ideal archery draw length from your arm span or height.
Bedridden Patient Height Calculator
Estimate a bedridden patient's height from knee height, ulna length, or demispan.
Health & Fitness → Dietary
Calorie Calculator
Estimate your daily calorie needs (BMR & TDEE) for maintenance, weight loss, or muscle gain.
BMR Calculator
Calculate your Basal Metabolic Rate using the Mifflin-St Jeor equation.
Harris-Benedict Calculator
Calculate your Basal Metabolic Rate using the Harris-Benedict equation.
Katch-McArdle Calculator
Calculate BMR using the Katch-McArdle formula based on lean body mass.
BEE Calculator
Calculate your Basal Energy Expenditure at complete rest.
RMR Calculator
Calculate your Resting Metabolic Rate, the calories burned at rest.
TDEE Calculator
Calculate your Total Daily Energy Expenditure based on activity level.
EER Calculator
Calculate your Estimated Energy Requirement based on age, sex, and activity.
Calorie Deficit Calculator
Calculate the calorie deficit needed to lose weight at your target pace.
Calorie Intake Calculator
Get a quick estimate of your daily calorie intake target.
Maintenance Calorie Calculator
Calculate the calories needed to maintain your current weight.
Meal Calorie Calculator
Estimate the calories in a meal from its ingredients and portions.
Macro Calculator
Calculate your ideal daily protein, carb, and fat split based on your goals.
Body Recomposition Calculator
Plan calorie and protein targets for losing fat while building muscle.
IIFYM Calculator
Calculate flexible dieting macros using the If It Fits Your Macros method.
Protein Calculator
Calculate your daily protein needs based on weight, goal, and activity level.
Carb Calculator
Calculate your daily carbohydrate needs based on your calorie goal.
Net Carbs Calculator
Calculate net carbs by subtracting fiber and sugar alcohols from total carbs.
Carb Counting Calculator
Add up carbs from any meal using common household servings.
Weight Watchers Points Calculator
Estimate points for any food and get your personalized daily points budget.
Fat Intake Calculator
Calculate your recommended daily fat intake based on total calories.
Fiber Calculator
Calculate your recommended daily dietary fiber intake.
Keto Calculator
Calculate your macro targets for a ketogenic diet.
Added Sugar Intake Calculator
Check your added sugar intake against recommended daily limits.
Diet Risk Score Calculator
Score your diet quality and everyday health risk from a 10-question habits quiz.
Sodium in Salt Calculator
Convert between salt and sodium amounts on nutrition labels.
Micronutrient Calculator
Check your intake of key vitamins and minerals against daily recommendations.
Vitamin Calculator
Estimate your daily vitamin needs based on age and sex.
Vitamin A Calculator
Calculate your recommended daily Vitamin A intake, RDA, and safe upper limit.
Vitamin D Calculator
Calculate your recommended daily Vitamin D intake, RDA, sun exposure, and blood test level.
DRI Calculator
Calculate Dietary Reference Intake values for key nutrients.
Diet Risk Score Calculator
Score your diet quality and health risk based on eating habits.
Weight Loss Percentage Calculator
Calculate the percentage of body weight lost between two dates.
Weight Gain Calculator
Calculate the calorie surplus needed to gain weight at your target pace.
Gastric Sleeve Weight Loss Calculator
Project expected weight loss after gastric sleeve surgery over time.
Weight Watchers Points Calculator
Estimate points values for foods on a points-based diet system.
Quarantine Activity Calculator
Estimate calories burned from home workouts and everyday indoor activity.
ABV & Proof Calculator
Calculate alcohol by volume from gravity readings, convert ABV to proof, and work out standard drinks, calories, dilution, and blending.
BAC Calculator
Estimate your Blood Alcohol Concentration from your drinks, weight, and time using the Widmark formula, with impairment stage and sober-up time.
Health & Fitness → Diabetes
Blood Sugar Converter
Convert blood sugar readings between mg/dL and mmol/L.
A1c Calculator
Convert Hemoglobin A1c percentage to estimated average blood glucose.
Estimated Average Glucose Calculator
Estimate your average blood glucose from an A1c reading.
Diabetes Risk Calculator
Screen your risk of developing type 2 diabetes based on key health factors.
Diabetic Ketoacidosis Calculator
Support DKA assessment using key labs like glucose, pH, and anion gap.
Glycemic Index Calculator
Look up how quickly a food raises blood sugar based on its glycemic index.
Glycemic Load Calculator
Calculate the glycemic load of a food based on glycemic index and carb content.
HOMA-IR Calculator
Estimate insulin resistance from fasting glucose and insulin levels.
QUICKI Calculator
Calculate the Quantitative Insulin Sensitivity Check Index.
Insulin Dosage Calculator
Estimate insulin dosage based on carb intake and correction factor.
Insulin-to-Carb Ratio Explainer
Learn how the insulin-to-carb ratio and correction factor formula works, with worked examples and a practice quiz.
Warsaw Method Calculator
Learn how the Warsaw method estimates extended insulin coverage for high-fat, high-protein meals using fat-protein units.
Health & Fitness → Metabolic Disorders
Cholesterol Ratio Calculator
Calculate your total cholesterol to HDL ratio for heart health assessment.
Cholesterol Units Converter
Convert cholesterol readings between mg/dL and mmol/L.
LDL Calculator
Estimate LDL cholesterol using the Friedewald equation.
VLDL Calculator
Estimate VLDL cholesterol from your triglyceride level.
Metabolic Syndrome Calculator
Screen for metabolic syndrome based on waist size, blood pressure, and labs.
Gout Diagnosis Calculator
Support gout diagnosis using a clinical scoring system.
SAAG Calculator
Calculate the Serum-Ascites Albumin Gradient to classify ascites causes.
Anion Gap & Serum Osmolar Gap Solver
Calculate the anion gap (with albumin correction) and serum osmolar gap from your basic metabolic panel, with instant interpretation.
Blood pH & Henderson-Hasselbalch Blood Gas
Calculate blood pH from PaCO2 and HCO3 with the Henderson-Hasselbalch equation, identify respiratory or metabolic acidosis/alkalosis, and check compensation with Winter's formula.
Health & Fitness → Army
ACFT Calculator
Score the Army Combat Fitness Test events and get your total ACFT score.
APFT Calculator
Score the Army Physical Fitness Test — push-ups, sit-ups, and 2-mile run.
AFT Calculator
Score the US Army Fitness Test events and total.
Air Force PT Calculator
Score the Air Force Physical Training test based on official standards.
Army Body Fat Calculator
Calculate body fat percentage using the U.S. Army tape-test method.
Navy Body Fat Calculator
Calculate body fat percentage using the U.S. Navy circumference method for service standards.
Navy PRT Calculator
Score the Navy Physical Readiness Test — run, push-ups, and plank or curl-ups.
Health & Fitness → Sleep
Sleep Calculator
Find the best bedtime or wake-up time based on full sleep cycles.
Sleep Debt Calculator
Calculate accumulated sleep debt from your recent sleep schedule.
Epworth Sleepiness Scale Calculator
Score your daytime sleepiness using the Epworth Sleepiness Scale.
Pediatric Epworth Sleepiness Scale Calculator
Score a child's daytime sleepiness using the pediatric Epworth scale.
AHI Calculator
Calculate the Apnea-Hypopnea Index to assess sleep apnea severity.
STOP-BANG Calculator
Screen your risk of obstructive sleep apnea using the STOP-BANG questionnaire.
Health & Fitness → Fitness & Exercise
One Rep Max Calculator
Estimate your one-rep max lift from a weight and rep count.
VO2 Max Calculator
Estimate your VO2 max, a key measure of aerobic fitness.
Target Heart Rate Calculator
Calculate your target heart rate zones for effective cardio training.
Calories Burned Calculator
Estimate calories burned during a workout based on activity, weight, and duration.
Running Pace Calculator
Calculate your running pace, finish time, or target splits for a race.
Steps to Calories Calculator
Convert your daily step count into an estimated calorie burn.
Water Intake Calculator
Calculate your recommended daily water intake based on weight and activity.
Health & Fitness → Pregnancy & Pediatric
Pregnancy Calculator
Track pregnancy week-by-week and estimate your due date.
Due Date Calculator
Estimate your baby's due date from your last period or conception date.
Conception Calculator
Estimate the likely conception date based on your due date or last period.
Ovulation Calculator
Predict your fertile window and likely ovulation day.
Pregnancy Weight Gain Calculator
Check your pregnancy weight gain against recommended ranges by trimester.
Child Height Predictor
Predict a child's adult height based on parents' heights.
Growth Percentile Calculator
Check a child's height and weight percentile against standard growth charts.
Apgar Score Calculator
Calculate a newborn's Apgar score from the five standard clinical signs.
Math
Math → Basic Calculators
Scientific Calculator
A full-featured scientific calculator with trig, log, and exponent functions.
Percentage Calculator
Calculate percentages, percentage change, and percent of a value.
Fraction Calculator
Add, subtract, multiply, and divide fractions with step-by-step results.
Average Calculator
Calculate the average (mean) of a list of numbers.
Ratio Calculator
Simplify ratios, scale ratios, and solve for a missing value in a proportion.
Decimal Calculator
Add, subtract, multiply, and divide decimal numbers with precision.
Exponent Calculator
Calculate powers, roots, and exponent expressions including negative and fractional exponents.
Log Calculator
Calculate logarithms in any base, including natural log (ln) and common log (log10).
Math → Geometry
Triangle Calculator
Solve triangle sides, angles, area, and perimeter from known values.
Circle Calculator
Calculate the area, circumference, radius, or diameter of a circle.
Square Calculator
Calculate the area, perimeter, and diagonal of a square.
Rectangle Calculator
Calculate the area, perimeter, and diagonal of a rectangle.
Trapezoid Calculator
Calculate the area and perimeter of a trapezoid from its sides and height.
Polygon Calculator
Calculate the area, perimeter, and interior angles of any regular polygon.
Pythagorean Calculator
Solve for a missing side of a right triangle using the Pythagorean theorem.
Math → Geometry → Coordinate Geometry
Distance Calculator
Calculate the distance between two points on a coordinate plane.
Midpoint Calculator
Find the midpoint between two coordinate points.
Slope Calculator
Calculate the slope of a line between two points.
Line Equation Calculator
Find the equation of a line from two points or a point and slope.
Math → Mensuration (3D)
Cube Calculator
Calculate the volume, surface area, and diagonal of a cube.
Cuboid Calculator
Calculate the volume, surface area, and diagonal of a cuboid.
Sphere Calculator
Calculate the volume and surface area of a sphere from its radius.
Cylinder Calculator
Calculate the volume and surface area of a cylinder.
Cone Calculator
Calculate the volume and surface area of a cone.
Prism Calculator
Calculate the volume and surface area of a prism.
Math → Statistics
Mean Calculator
Calculate the mean (average) of a data set.
Median Calculator
Calculate the median of a data set.
Mode Calculator
Calculate the mode of a data set.
Standard Deviation Calculator
Calculate population and sample standard deviation from any data set.
Variance Calculator
Calculate population and sample variance from any data set.
Z Score Calculator
Calculate the Z-score (standard score) from a raw score, mean, and standard deviation.
Correlation Calculator
Calculate the Pearson correlation coefficient (r) from paired x, y data.
Regression Calculator
Calculate the linear regression line equation (y = mx + c) and R² from paired x, y data.
Math → Probability
Probability Calculator
Calculate the probability of single and combined events.
Conditional Probability
Calculate the probability of an event given that another event has occurred.
Normal Distribution
Probability calculator for the bell curve — find the area under the curve for any mean and standard deviation.
Binomial Distribution
Probability calculator for a fixed number of trials (n) and success probability (p).
Poisson Distribution
Find the probability of a given number of events occurring in a fixed interval.
Uniform Distribution
Calculate probabilities for a continuous or discrete uniform distribution.
Hypergeometric Distribution
Calculate probabilities for sampling without replacement from a finite population.
Permutation Calculator
Calculate nPr — the number of ways to arrange r items from a set of n.
Combination Calculator
Calculate nCr — the number of ways to choose r items from a set of n.
Bayes Theorem Calculator
Calculate posterior probability using Bayes' theorem.
Math → Algebra
Equation Solver
Solve algebraic equations for an unknown variable.
Linear Equation
Solve linear equations and systems of linear equations.
Quadratic Equation
Solve quadratic equations using the quadratic formula, with real and complex roots.
Polynomial Calculator
Solve any polynomial equation with steps, rational roots, and a plotted curve diagram.
Matrix Calculator
Add, subtract, multiply matrices, and find inverses and transposes.
Determinant Calculator
Calculate the determinant of a square matrix.
Complex Number Calculator
Add, subtract, multiply, and divide complex numbers.
Binomial Expansion
Expand binomial expressions using the binomial theorem.
Math → Calculus
Limit Calculator
Calculate the limit of a function as it approaches a given value.
Derivative Calculator
Calculate the derivative of a function with step-by-step differentiation.
Integral Calculator
Calculate definite and indefinite integrals with step-by-step integration.
Partial Derivative
Calculate partial derivatives of multivariable functions.
Gradient Calculator
Calculate the gradient vector of a multivariable function.
Differential Equation
Solve ordinary differential equations.
Math → Trigonometry
Sin Calculator
Calculate the sine of an angle in degrees or radians.
Cos Calculator
Calculate the cosine of an angle in degrees or radians.
Tan Calculator
Calculate the tangent of an angle in degrees or radians.
Cot Calculator
Calculate the cotangent of an angle in degrees or radians.
Sec Calculator
Calculate the secant of an angle in degrees or radians.
Cosec Calculator
Calculate the cosecant of an angle in degrees or radians.
Right Triangle Calculator
Solve a right triangle for missing sides and angles.
Law of Cosines
Solve a triangle's sides and angles using the law of cosines.
Angle of Depression Calculator
Find the angle of depression, height, or distance with a diagram.
Math → Sequences & Series
Arithmetic Sequence
Find any term and the sum of an arithmetic sequence.
Geometric Sequence
Find any term and the sum of a geometric sequence.
Fibonacci Series
Find any Fibonacci term, the sum of the series, or a value's position.
Arithmetic Series
Calculate the sum of an arithmetic series.
Geometric Series
Calculate the sum of a finite or infinite geometric series.
Math → Vectors
Math → Unit Converters
Length
Convert between metric and imperial length units.
Area
Convert between metric and imperial area units.
Volume
Convert between metric and imperial volume units.
Weight
Convert between metric and imperial weight units.
Temperature
Convert between Celsius, Fahrenheit, and Kelvin.
Speed
Convert between km/h, mph, m/s, and knots.
Time
Convert between seconds, minutes, hours, days, and more.
Angle
Convert between degrees, radians, and gradians.
Math → Date & Time
Age Calculator
Find your exact age in years, months, days, and total hours.
Date Difference Calculator
Find the difference between two dates, including or excluding weekends and holidays.
Add/Subtract Days Calculator
Add or subtract days, weeks, or months from a date to find a future or past date.
Time Duration Calculator
Calculate total working hours from a start time, end time, and break deductions.
Time Zone Converter
Compare real-time offsets between multiple cities for international meetings and travel.
Countdown Calculator
See the exact time left until a target date, live in days, hours, minutes, and seconds.
Business Days Calculator
Calculate workdays for project deadlines, filtering out weekends and custom holidays.
Physics
Physics → Mechanics
Speed Calculator — How Fast Are You Really Going?
Plug in distance and time and get your exact speed instantly — with every step shown.
Velocity Calculator (With Direction!)
Speed alone won't cut it — find velocity with direction from displacement and time in one click.
Acceleration Calculator — Solve for Any Variable
From 0 to solved: find acceleration, final velocity, initial velocity, or time using a = (v − u)/t.
Distance Calculator — No More Guessing
Know your speed and time? Get the exact distance traveled in seconds, fully worked out.
Displacement Calculator — Position Nailed Down
Combine initial position, velocity, acceleration, and time to pinpoint displacement instantly.
Time Calculator — Work Backward From Motion
Rearrange the motion equations for you — find time from distance, speed, or acceleration.
Average Speed Calculator — The Trick Everyone Gets Wrong
It's not just the mean of your speeds — get the real average across every leg of a trip.
Force Calculator — Newton's Second Law Made Easy
F = ma solved instantly, with clean step-by-step working you can actually follow.
Weight Calculator — Your Weight on Earth (or Any Planet)
Mass isn't weight! Find true weight from mass and gravity, W = mg, in one quick step.
Momentum Calculator — Mass in Motion
Get linear momentum from mass and velocity instantly, p = mv, with full working shown.
Impulse Calculator — The Force-Time Shortcut
Solve impulse from force and time, or straight from a change in momentum — your choice.
Work Calculator — Are You Really Doing 'Work'?
Find the physics answer for work done from force, displacement, and angle in seconds.
Power Calculator — How Fast Is Work Getting Done?
Turn work done and time taken into mechanical power output instantly.
Kinetic Energy Calculator — Energy of Motion
KE = ½mv² solved in one step — see exactly how mass and speed drive energy.
Potential Energy Calculator — Stored Energy, Revealed
Find gravitational potential energy from mass, height, and gravity instantly.
Mechanical Energy Calculator — The Full Picture
See kinetic and potential energy combined into one total mechanical energy value.
Efficiency Calculator — Is Your Machine Wasting Energy?
Compare output vs input energy and get the real efficiency percentage instantly.
Projectile Motion Calculator — Predict the Perfect Arc
Get range, max height, and time of flight for any launch angle, instantly calculated.
Free Fall Calculator — Gravity Does the Rest
Find velocity, distance fallen, and time for anything dropping under gravity alone.
Centripetal Force Calculator — What Keeps It Spinning?
Find the exact force needed to keep an object moving in a circle, instantly.
Centripetal Acceleration Calculator — Circular Motion Solved
Get centripetal acceleration from velocity and radius in one quick calculation.
Torque Calculator — The Twisting Force Explained
Find torque from force, lever arm distance, and angle — instantly, with steps.
Angular Velocity Calculator — How Fast Is It Spinning?
Turn angle and time into angular velocity in a single, clear calculation.
Angular Acceleration Calculator — Spin Speed Changing?
Find angular acceleration from a change in angular velocity over time, instantly.
Inclined Plane Calculator — Ramps, Slopes & Sliding Objects
Get force, acceleration, and normal force on any incline — solved step by step.
Friction Calculator — How Much Grip Do You Really Have?
Find frictional force instantly from normal force and coefficient of friction.
Physics → Electricity & Magnetism
Ohm's Law Calculator
Calculate voltage, current, or resistance using Ohm's Law, V = IR.
Voltage Calculator
Calculate voltage from current and resistance, or from power and current.
Current Calculator
Calculate electric current from voltage and resistance.
Resistance Calculator
Calculate electrical resistance from voltage and current.
Power Calculator
Calculate electrical power from voltage, current, or resistance.
Electrical Energy Calculator
Calculate electrical energy consumption from power and time.
Series Resistance Calculator
Calculate total resistance for resistors connected in series.
Parallel Resistance Calculator
Calculate total resistance for resistors connected in parallel.
Capacitor Calculator
Calculate capacitance, charge, and energy stored in a capacitor.
RC Circuit Calculator
Calculate the time constant and charging/discharging behavior of an RC circuit.
Magnetic Field Calculator
Calculate magnetic field strength from current and distance.
Lorentz Force Calculator
Calculate the force on a charged particle moving through a magnetic field.
Induced EMF Calculator
Calculate induced EMF from changing magnetic flux using Faraday's Law.
Transformer Calculator
Calculate voltage, current, and turns ratio for a transformer.
Physics → Thermodynamics
Heat Calculator
Calculate heat energy transferred using Q = mcΔT.
Specific Heat Calculator
Calculate specific heat capacity from mass, heat energy, and temperature change.
Latent Heat Calculator
Calculate the heat energy required for a phase change.
Thermal Expansion Calculator
Calculate the change in length, area, or volume due to a temperature change.
Ideal Gas Law Calculator
Calculate pressure, volume, temperature, or moles using PV = nRT.
Ideal Gas Pressure Calculator
Find gas pressure from PV = nRT, a pressure change, or a partial pressure with Dalton's Law.
Ideal Gas Volume Calculator
Find gas volume from PV = nRT, a volume change, or a new volume with Avogadro's Law.
Ideal Gas Temperature Calculator
Find gas temperature from PV = nRT, a pressure/volume change, or Gay-Lussac's Law.
Boyle's Law Calculator
Calculate pressure or volume of a gas at constant temperature.
Charles' Law Calculator
Calculate volume or temperature of a gas at constant pressure.
Gay-Lussac's Law Calculator
Calculate pressure or temperature of a gas at constant volume.
Combined Gas Law Calculator
Calculate pressure, volume, or temperature using the combined gas law.
Avogadro's Law Calculator
Calculate final volume, final moles, initial volume, or initial moles of a gas using V1/n1 = V2/n2.
Dalton's Law of Partial Pressures Calculator
Add partial pressures to find total pressure, or solve for a partial pressure, mole fraction, or total pressure.
Graham's Law of Effusion & Diffusion Calculator
Calculate effusion or diffusion rate, or molar mass, using Rate1/Rate2 = sqrt(M2/M1).
Carnot Efficiency Calculator
Calculate the maximum theoretical efficiency of a heat engine.
Physics → Waves & Oscillations
Wave Speed Calculator
Calculate wave speed from frequency and wavelength, v = fλ.
Frequency Calculator
Calculate frequency from period, or from wave speed and wavelength.
Wavelength Calculator
Calculate wavelength from wave speed and frequency.
Period Calculator
Calculate the period of oscillation from frequency.
SHM Calculator
Calculate displacement, velocity, and acceleration in simple harmonic motion.
Pendulum Calculator
Calculate the period of a simple pendulum from its length.
Doppler Effect Calculator
Calculate the observed frequency shift due to relative motion of source and observer.
Resonance Calculator
Calculate the resonant frequency of an oscillating system.
Physics → Optics
Lens Formula Calculator
Calculate image distance, object distance, or focal length using the lens formula.
Mirror Formula Calculator
Calculate image distance, object distance, or focal length using the mirror formula.
Magnification Calculator
Calculate the magnification of a lens or mirror.
Refractive Index Calculator
Calculate the refractive index of a medium from light speed or angle data.
Snell's Law Calculator
Calculate the angle of refraction using Snell's Law.
Critical Angle Calculator
Calculate the critical angle for total internal reflection.
Optical Power Calculator
Calculate the optical power of a lens from its focal length.
Physics → Modern Physics
Photon Energy Calculator
Calculate the energy of a photon from its frequency or wavelength.
Photoelectric Effect Calculator
Calculate the kinetic energy of emitted electrons using the photoelectric equation.
de Broglie Wavelength Calculator
Calculate the de Broglie wavelength of a moving particle.
Half-Life Calculator
Calculate the remaining quantity of a radioactive substance after a given time.
Radioactive Decay Calculator
Calculate the decay of a radioactive substance over time.
Carbon Dating & Radiometric Age Calculator
Estimate the age of a sample using carbon-14 or other radiometric dating isotopes.
Mass-Energy Calculator (E = mc²)
Calculate the energy equivalent of mass using Einstein's E = mc².
Nuclear Binding Energy Calculator
Calculate the nuclear binding energy from mass defect.
Physics → Fluids
Density Calculator
Calculate density from mass and volume, ρ = m/V.
Pressure Calculator
Calculate pressure from force and area, P = F/A.
Hydrostatic Pressure Calculator
Calculate the pressure exerted by a fluid at a given depth.
Buoyant Force Calculator
Calculate the buoyant force on an object using Archimedes' principle.
Pascal's Law Calculator
Calculate force or pressure transmission in a hydraulic system using Pascal's Law.
Flow Rate Calculator
Calculate the volumetric flow rate of a fluid from velocity and cross-sectional area.
Bernoulli Calculator
Calculate pressure, velocity, or height using Bernoulli's equation.
Physics → Gravitation
Universal Gravitation Calculator
Calculate the gravitational force between two masses using Newton's law of gravitation.
Escape Velocity Calculator
Calculate the minimum velocity needed to escape a planet's gravity.
Orbital Velocity Calculator
Calculate the velocity needed to maintain a stable orbit.
Gravity Calculator
Calculate the acceleration due to gravity at a given altitude or on another planet.
Planet Weight Calculator
Calculate your weight on different planets based on their gravity.
Physics → Rotational Motion
RPM Calculator
Calculate rotational speed in revolutions per minute.
Angular Momentum Calculator
Calculate angular momentum from moment of inertia and angular velocity.
Rotational Kinetic Energy Calculator
Calculate the kinetic energy of a rotating object.
Moment of Inertia Calculator
Calculate the moment of inertia for common shapes and rotation axes.
Physics → Unit Converters
Length Converter
Convert between metric and imperial length units used in physics problems.
Mass Converter
Convert between kilograms, grams, pounds, and other mass units.
Temperature Converter
Convert between Celsius, Fahrenheit, and Kelvin.
Pressure Converter
Convert between pascal, atm, bar, psi, and other pressure units.
Energy Converter
Convert between joules, calories, kWh, and other energy units.
Force Converter
Convert between newtons, dynes, pounds-force, and other force units.
Speed Converter
Convert between m/s, km/h, mph, and other speed units.
Power Converter
Convert between watts, horsepower, and other power units.
Electric Unit Converter
Convert between amperes, volts, ohms, and other electrical units.
Chemistry
Chemistry → Mole Concept, Atomic & Nuclear
Molar Mass / Molecular Weight Calculator
Find the molar mass (molecular weight) of any chemical formula, with a full percent composition breakdown and step-by-step working.
Grams to Moles Calculator
Convert mass to moles, or moles back to mass, using the molar mass of any chemical formula, with particle count and step-by-step working.
Moles to Grams Calculator
Convert moles to mass, or grams back to moles, using the molar mass of any chemical formula, with a mole-to-mass scaling table, particle count, and step-by-step working.
Moles to Molecules / Atoms Converter
Convert moles to the number of molecules, formula units, or atoms using Avogadro's number, with a per-element atom breakdown and step-by-step working.
Avogadro's Number Calculator
Convert moles to the number of atoms, molecules, ions, or any other particle using Avogadro's number, work backward from a particle count to moles, or start from a mass and chemical formula — with a 'how big is this number' real-world comparison and full step-by-step working.
Percent Composition by Mass Calculator
Find the percent composition by mass of every element in any chemical formula, convert those percentages into real grams for a sample of any size, work backward to the sample size needed for a target element mass, and see full step-by-step working.
Average Atomic Mass & Isotope Abundance
Calculate an element's average atomic mass from a list of isotopes and their percent abundances, or work backward to find a missing isotope abundance from two isotope masses and a known average mass, with built-in element presets and full step-by-step working.
Electron Configuration Finder
Find the full and noble-gas-shorthand electron configuration of any element or ion — type a symbol, name, or atomic number and get an orbital box diagram, an electrons-per-shell chart, and full step-by-step working.
Quantum Numbers Calculator
Find the principal, azimuthal, magnetic, and spin quantum numbers (n, l, mₗ, mₛ) of the last electron in any element or ion, or check whether your own set of quantum numbers is a valid combination — with an orbital box diagram and full step-by-step working.
Valence Electrons Finder
Find the number of valence electrons in any element or ion — type a symbol, name, or atomic number and get a Lewis dot diagram, an octet-rule check, and full step-by-step working.
Atomic & Ionic Radius Comparison
Compare the atomic radius or ionic radius of any two elements or ions in picometers — see which is bigger, a scaled size diagram, a periodic trend chart, and full step-by-step reasoning behind the result.
Electronegativity Difference & Bond Polarity
Find the electronegativity difference (ΔEN) between any two elements, see whether the bond is nonpolar covalent, polar covalent, or ionic, get the estimated percent ionic character and dipole direction, comparison and periodic trend charts, and full step-by-step working.
Nuclear Binding Energy & Mass Defect
Find the mass defect, total nuclear binding energy, and binding energy per nucleon for any nuclide, with full step-by-step working and a labelled nucleus diagram.
Radioactive Decay & Half-Life
Calculate the remaining quantity of a radioactive substance, the elapsed time, the decay constant, or the half-life itself using N = N0.e^(-lambda.t), with full step-by-step working and a labelled decay curve.
Carbon Dating & Radiometric Age Calculator
Find the age of a sample from carbon-14 or other radiometric isotopes, the percentage of parent isotope remaining, or the original quantity, with years-before-present conversion, full step-by-step working, and a decay diagram.
Chemistry → Stoichiometry & Reaction Engineering
Chemical Equation Balancer
Balance any chemical equation instantly with the smallest whole-number coefficients, an element-by-element atom check, and step-by-step working.
Limiting Reactant Solver
Find the limiting reactant, the excess reactant left over, and the theoretical yield of every product, with the equation balanced automatically and full step-by-step working.
Theoretical Yield Calculator
Find the theoretical yield of any product from any set of reactant amounts, with the limiting reactant identified automatically, an optional percent yield check, and full step-by-step working.
Percent Yield Calculator
Calculate percent yield, actual yield, or theoretical yield instantly with unit conversion, a labeled efficiency gauge, and full step-by-step working.
Actual Yield & Excess Reactant Finder
Predict the actual yield of any product from a percent yield, and find exactly how much of every excess reactant is left over, with the limiting reactant identified automatically and full step-by-step working.
Empirical Formula Calculator
Find the empirical formula from percent composition or lab masses, with mole ratios, whole-number subscripts, empirical formula mass, and an optional molecular formula — all with full step-by-step working.
Molecular Formula Calculator
Find the true molecular formula from an empirical formula and molar mass, or straight from percent composition and molar mass, with an atom-by-atom breakdown and full step-by-step working.
Oxidation State / Number Calculator
Find the oxidation number of every element in a compound or ion — type a formula like KMnO4 or Cr2O7^2- and get an instant, rule-by-rule breakdown with a chart, a balance check, and full step-by-step working.
Redox Half-Reaction Balancer
Balance any oxidation or reduction half-reaction in acidic or basic solution, with electrons, water, and H+/OH- added automatically, a full atom-and-charge check, and an advanced combiner that builds the overall balanced redox equation from two half-reactions.
Combustion Analysis (CHNS) Calculator
Turn CO2 and H2O combustion masses, or a CHNS elemental analyzer printout, into %C, %H, %N, %S and %O by difference, then build the empirical and molecular formula automatically — with a degree-of-unsaturation check and full step-by-step working.
Multi-Step Synthesis Overall Yield
Calculate the overall cumulative percent yield of a multi-step reaction sequence by multiplying every step's yield together, with final product mass, required starting material, and a full step-by-step cascade breakdown.
Atom Economy Calculator (Green Chemistry)
Find the percent atom economy of any balanced reaction from reactant and product formulas, with by-product waste mass, a mass-flow chart, reaction mass efficiency, E-factor, and a full step-by-step green chemistry breakdown.
Environmental E-Factor Calculator
Find the Sheldon E-factor of any chemical process from your raw material and product masses, with waste breakdown by category, mass intensity, mass productivity, an industry benchmark chart, and full step-by-step working.
Reaction Stoichiometry Mass-to-Volume
Convert the mass of any reactant or product into the volume of a gas it forms (or the reverse) using a balanced equation and the real ideal gas law, with STP, IUPAC STP, NTP, room temperature, and custom condition presets, a species-by-species comparison, and full step-by-step working.
Gas Stoichiometry at STP/NTP
Solve any gas stoichiometry problem at STP, NTP, SATP, or custom conditions — convert freely between mass, moles, and gas volume for every species in a balanced equation, with a live molar volume readout, an Avogadro's Law volume-to-volume shortcut, and full step-by-step working.
Hydrate Water Content / Water of Crystallization
Find the percent water of crystallization in any hydrate formula like CuSO4·5H2O, or work out the water content and hydrate formula from before-and-after heating lab data, with a donut chart, common-hydrate comparisons, and full step-by-step working.
Gravimetric Analysis Factor Calculator
Find the gravimetric factor between any analyte and its weighed precipitate form (like Fe from Fe2O3, or Cl from AgCl), then convert a precipitate mass into the mass and percent of analyte in your sample, with a common-pair comparison chart and full step-by-step working.
Percent Purity & Sample Assay Calculator
Find percent purity from a pure substance mass and sample mass, size the impure sample needed for a target pure mass, or run a full analytical sample assay against a reference standard, with a purity benchmark chart and full step-by-step working.
Chemistry → Solutions, Concentrations & Lab Prep
Molarity Calculator
Calculate molarity, moles, solution volume, dilution, and solute mass with step-by-step unit conversions.
Molality Calculator
Calculate molality, moles of solute, solvent mass, and solute mass, plus freezing point depression and boiling point elevation, with step-by-step unit conversions.
Normality & Equivalent Mass Calculator
Calculate normality, equivalents, solution volume, solute mass, equivalent mass (equivalent weight), and molarity-to-normality conversion, with n-factor presets and step-by-step working.
Dilution Calculator
Solve C1V1=C2V2 for stock concentration, target concentration, stock volume, or final volume, calculate ratio dilutions like 1:10, or build a full serial dilution table and dilution curve, with full step-by-step working.
Serial Dilution Solver
Build a full serial dilution series, solve backwards for the per-step factor and volumes needed to hit a target endpoint, or back-calculate CFU/mL from a plate colony count, with a dilution curve and full step-by-step working.
Mass Percent Concentration
Calculate mass percent concentration (% w/w) from solute and solvent mass, find the solute or solvent mass needed for a target percent, work out dilution water, convert mass percent to molarity, and convert freely between percent, ppm, and ppb, with full step-by-step working.
Volume Percent Concentration
Calculate volume percent concentration (% v/v) from solute and solvent volume, find the solute or solvent volume needed for a target percent, work out dilution volume, convert volume percent to molarity, and convert freely between percent, ppm, and ppb, with full step-by-step working.
Mass-by-Volume Percent
Calculate mass by volume percent concentration (% w/v) from solute mass and solution volume, find the solute mass or solution volume needed for a target percent, work out dilution volume, convert % w/v to molarity, convert % w/v to % w/w using density, and convert freely between percent, ppm, and ppb, with full step-by-step working.
PPM (Parts Per Million) Converter
Convert parts per million to percent, ppb, ppt, mg/L, mg/kg, and molarity, work out the solute mass needed to prepare a target ppm standard solution, and solve ppm dilutions, with full step-by-step working.
PPB (Parts Per Billion) Converter
Convert parts per billion to percent, ppm, ppt, µg/L, µg/kg, and molarity, work out the solute mass needed to prepare a target ppb standard solution, solve ppb dilutions, and convert gas-phase ppb (ppbv) to µg/m³ for air quality, with full step-by-step working.
Mole Fraction Calculator
Find the mole fraction of every component in a mixture of up to eight components from mass and molar mass, convert a solute's mole fraction into molality, molarity, and mass percent, and calculate vapor pressure with Raoult's Law, with full step-by-step working.
Solution Density & Specific Gravity
Calculate solution density from mass and volume, solve for mass or volume, convert density to specific gravity (SG) and back, and get an automatic Baumé degree reading, with multiple water reference temperatures and full step-by-step working.
Solution Blending / Concentration Mixing
Find the resulting concentration when blending two solutions, or work out exactly how much of each stock solution you need to hit a target concentration and volume or mass, using molarity or mass percent, with full step-by-step alligation working.
Stock Solution Reconstitution Solver
Find how much diluent to add to a powder or lyophilized vial to hit a target concentration, work out the concentration you already made, or calculate the exact draw volume for a dose, with purity, powder displacement, molarity conversion, and full step-by-step working.
Osmolality & Osmolarity Calculator
Calculate osmolarity (mOsm/L) and osmolality (mOsm/kg) from molarity or solute mass with a van't Hoff dissociation factor and tonicity check, or work out calculated serum osmolarity and the osmolar gap from sodium, glucose, and BUN, with full step-by-step working.
Ionic Strength Calculator
Calculate the ionic strength of a solution from a custom ion list or a common salt preset, find Debye-Hückel and Davies activity coefficients, and solve ionic strength dilutions, with a contribution chart and full step-by-step working.
Molarity to PPM Converter
Convert molarity (mol/L) to ppm and mg/L, convert ppm back to molarity, work out how much solute to weigh for a target molar or ppm solution, and solve stock-to-working ppm dilutions, with a common-solute quick-fill list and full step-by-step working.
PPM to Molarity Converter
Convert ppm and mg/L into molarity (mol/L), convert molarity back to ppm, find the solute mass needed for a target ppm or molar standard, and solve stock-to-working ppm dilutions, with a common-solute quick-fill list and full step-by-step working.
Mass Percentage to Molarity Converter
Convert mass percent (% w/w) into molarity (mol/L), convert molarity back to mass percent, find the solute mass needed to prepare a target mass % solution, and solve stock-to-working mass % dilutions, with a common-solute quick-fill list and full step-by-step working.
Specific Gravity to Molarity Converter
Convert specific gravity (SG) and mass percent into molarity (mol/L), convert molarity back to SG and mass percent, find the solute mass needed to prepare a target solution by volume, and solve stock-to-working SG dilutions, with selectable water references, a common-solute quick-fill list, and full step-by-step working.
Buffer Solution Volume & Mass Calculator
Work out exactly how much acid and conjugate base to weigh out or mix from stock solutions to make a buffer at any target pH, check the pH of a buffer you've already made, and dilute a buffer stock without shifting its pH, with a built-in library of common buffer systems (acetate, phosphate, Tris, citrate, bicarbonate, HEPES, MES, borate, glycine, ammonia) and full step-by-step working.
Solvent Evaporation & Concentration Increase
Find the new concentration after solvent evaporates from a solution, work out how much solvent needs to evaporate to hit a target concentration or mass percent (% w/w), and estimate the evaporation time from a known rate, with full step-by-step working.
Chemistry → Acids, Bases, pH & Ionic Equilibrium
pH Calculator
Calculate pH, pOH, [H+] and [OH-] for any solution — strong acids, strong bases, weak acids, weak bases, and Henderson-Hasselbalch buffers — with full step-by-step working.
pOH Calculator
Calculate pOH, pH, [OH-] and [H+] for any solution — strong bases, strong acids, weak bases, weak acids, and Henderson-Hasselbalch buffers — with full step-by-step working.
H+ to pH & pH to H+ Converter
Convert hydrogen ion concentration [H+] to pH in mol/L, mmol/L, µmol/L or nmol/L, convert pH back to [H+] in your chosen unit, and compare two pH values with a built-in acidity ratio tool, with full step-by-step working.
Strong Acid pH Calculator
Find the pH of any strong acid from molarity with common-acid presets, work out the exact dilution needed to reach a target pH, or calculate the combined pH after mixing two acid solutions, with an automatic correction for water autoionization at very dilute concentrations and full step-by-step working.
Strong Base pH Calculator
Find the pH of any strong base from molarity with common-base presets, work out the exact dilution needed to reach a target pH, or calculate the combined pH after mixing two base solutions, with an automatic correction for water autoionization at very dilute concentrations and full step-by-step working.
Weak Acid pH & Ka Calculator
Find the pH and percent dissociation of any weak acid from concentration and Ka, back-calculate Ka and pKa from a measured pH, or find the concentration needed to hit a target pH, with the exact ICE-table quadratic solved every time and full step-by-step working.
Weak Base pH & Kb Calculator
Find the pH, pOH and percent ionization of any weak base from concentration and Kb, back-calculate Kb and pKb from a measured pH, or find the concentration needed to hit a target pH, with the exact ICE-table quadratic solved every time and full step-by-step working.
pKa & pKb Converter
Convert Ka to pKa or pKa back to Ka, convert Kb to pKb or pKb back to Kb, and find the full conjugate acid-base pair — Ka, pKa, Kb and pKb together — from just one known value using pKa + pKb = 14, with acid/base strength classification and full step-by-step working.
Henderson-Hasselbalch Buffer pH
Calculate buffer pH from pKa and the conjugate base/weak acid ratio, work out exactly what ratio (and what concentrations) you need to hit a target pH, or back-calculate pKa and Ka from a measured pH — with a buffer capacity (pKa ± 1) check, common buffer-system presets, and full step-by-step working.
Buffer Capacity Calculator
Calculate buffer capacity (β) from pKa, total concentration and pH, estimate the pH change after adding a known amount of strong acid or base, or find the total concentration needed to hit a target buffer capacity — with a live buffer capacity curve, common buffer-system presets, and full step-by-step working.
Acid-Base Titration Equivalence Point
Find the exact volume of titrant needed to reach the equivalence point and the resulting pH for strong acid/strong base, weak acid/strong base, and weak base/strong acid titrations, with a half-equivalence point check, common weak acid/base presets, a schematic titration curve, and full step-by-step working.
Neutralization Reaction Calculator
Mix any acid with any base and find the limiting reagent, the leftover acid or base, the resulting pH, the salt formed, moles of water produced, and the heat released — with common strong and weak acid/base presets, a calorimetry temperature-rise option, and full step-by-step working.
Polyprotic Acid Equilibrium Solver
Find the exact pH and full species distribution of diprotic and triprotic acids like H2CO3, H3PO4, H2C2O4, and H2SO4 from concentration and Ka1/Ka2/Ka3 using the full charge-balance equation, or explore the alpha-fraction distribution diagram at any chosen pH, with full step-by-step working.
Solubility Product Constant (Ksp)
Calculate the solubility product constant (Ksp) from molar solubility, find molar solubility from Ksp, work out the common-ion effect on solubility, or predict whether mixing two solutions will form a precipitate with a Q vs Ksp check — with 30+ built-in salts and full step-by-step working.
Molar Solubility from Ksp
Find molar solubility directly from Ksp and salt stoichiometry in mol/L, mmol/L, µmol/L, g/L, mg/L, and g/100mL, with an automatic USP-style solubility classification, a 30+ salt comparison ranking chart, and full step-by-step working.
Common Ion Effect Solubility Solver
Find how much a common ion suppresses the molar solubility of any sparingly-soluble salt, enter the common-ion concentration directly or calculate it from a source compound's mass, and see the percent suppression, a full solubility-vs-concentration curve, and complete step-by-step working.
Salt Hydrolysis pH Calculator
Find the pH of any salt solution — salts of a weak acid and strong base, a strong acid and weak base, a weak acid and weak base, or a neutral strong-strong salt — with built-in salt presets, percent hydrolysis, and complete step-by-step working.
Isoelectric Point (pI) Calculator
Find the isoelectric point of any of the 20 standard amino acids from their exact pKa values, or paste a peptide/protein sequence to estimate its overall pI from residue counts, with a net-charge-vs-pH curve and complete step-by-step working.
Chemistry → Gas Laws & Fluid Behavior
Ideal Gas Law Solver
Solve PV = nRT for pressure, volume, temperature, or moles of gas — enter mass and molar mass instead of moles (type a chemical formula and the molar mass fills itself in), quick-fill STP, IUPAC STP, NTP, or room conditions, and get gas density with full step-by-step working.
Ideal Gas Pressure Calculator
Find gas pressure from PV = nRT, from a pressure/volume/temperature change, or from a partial pressure using Dalton's Law, with full step-by-step working.
Ideal Gas Volume Calculator
Find gas volume from PV = nRT, from a pressure/temperature change, or from a change in moles using Avogadro's Law, with full step-by-step working.
Ideal Gas Temperature Calculator
Find gas temperature from PV = nRT, from a pressure/volume change, or at constant volume using Gay-Lussac's Law, with full step-by-step working.
Combined Gas Law Calculator
Calculate final pressure, volume, or temperature using P1V1/T1 = P2V2/T2, with worked steps and a labelled gas-state diagram.
Boyle's Law Calculator
Calculate final pressure or volume of a gas at constant temperature using P1V1 = P2V2, with worked steps and a labelled piston diagram.
Charles's Law Calculator
Calculate final gas volume or temperature at constant pressure using V1/T1 = V2/T2, with worked steps and a labelled heated-gas diagram.
Gay-Lussac's Law Calculator
Calculate final pressure or temperature of a gas at constant volume using P1/T1 = P2/T2, with worked steps and a labelled sealed-container diagram.
Avogadro's Gas Law Calculator
Calculate final volume, final moles, initial volume, or initial moles of a gas at constant pressure and temperature using V1/n1 = V2/n2, with worked steps and a labelled particle-count diagram.
Van der Waals Real Gas Solver
Solve the Van der Waals real-gas equation (P + an²/V²)(V − nb) = nRT for pressure, volume, or temperature, with built-in constants for 14 common gases or your own custom a and b, a side-by-side comparison against the ideal gas law, the compressibility factor Z, and full step-by-step working.
Dalton's Law of Partial Pressures
Add up partial pressures to find total pressure, or solve for a partial pressure, mole fraction, or total pressure using Pi = xi × P_total, with worked steps and a labelled gas-mixture diagram.
Graham's Law of Effusion & Diffusion
Calculate effusion/diffusion rate or molar mass of a gas using Rate1/Rate2 = √(M2/M1), with worked steps and a labelled effusion-race diagram.
Gas Density & Molar Mass Calculator
Find the density of any gas from its molar mass, or work out an unknown gas's molar mass from a measured density, using ρ = PM/RT, with STP/NTP/SATP quick-fill conditions, a closest-common-gas match, a density-relative-to-air comparison, and full step-by-step working.
Root Mean Square (RMS) Speed of Gas
Calculate the root-mean-square (RMS) speed of gas molecules using vrms = √(3RT/M), plus the average speed and most probable speed from kinetic theory, from a chemical formula or molar mass and any temperature, with full step-by-step working.
STP / NTP Gas Volume Unit Converter
Convert a gas volume between STP, IUPAC STP, NTP, SATP, or any custom temperature and pressure using the combined gas law, convert freely between mL, L, m³, cm³, ft³, in³, and US gallons/quarts, and see the molar volume at both conditions, with full step-by-step working.
Chemistry → Thermodynamics & Thermochemistry
Gibbs Free Energy Calculator
Solve ΔG = ΔH − TΔS for Gibbs free energy, enthalpy, entropy, or temperature, check reaction spontaneity and find the crossover temperature, or switch to Advanced Tools to convert between ΔG° and the equilibrium constant K, apply the reaction quotient Q for real conditions, and get the standard cell potential E°, with full step-by-step working and charts.
Enthalpy Change Calculator
Find the enthalpy change (ΔH) of a reaction from calorimetry data using q = mcΔT, check whether it's exothermic or endothermic, or switch to Advanced Tools to solve ΔH°rxn with Hess's Law from standard enthalpies of formation, with full step-by-step working and reaction diagrams.
Entropy Change Calculator
Find the entropy change (ΔS) from heating or cooling using ΔS = nCp ln(T2/T1), from a phase change using ΔS = ΔH/T, or switch to Advanced Tools to calculate standard reaction entropy from tabulated S° values, with full step-by-step working and disorder diagrams.
Specific Heat Capacity Calculator
Solve q = mcΔT for specific heat capacity, heat energy, mass, or temperature change in J/(g·°C) or cal/(g·°C), or switch to Advanced Tools to convert specific heat into molar heat capacity and compare common substances, with full step-by-step working and diagrams.
Heat of Fusion & Vaporization Solver
Solve q = nΔH for melting, boiling, or sublimation energy, moles, or molar enthalpy using built-in substance presets, or switch to Advanced Tools for a full multi-stage heating or cooling curve, with full step-by-step working and diagrams.
Hess's Law Enthalpy Solver
Combine known reactions with reverse and multiplier controls to solve for a target reaction's ΔH using classic Hess's Law problems, or switch to Standard Enthalpies of Formation mode with a built-in ΔHf° quick-fill library for 30+ common substances, with full step-by-step working and diagrams.
Bond Dissociation Enthalpy Calculator
Estimate a reaction's ΔH from average bond dissociation enthalpies using a bonds-broken vs bonds-formed builder with worked example reactions, or switch to a Bond Energy Lookup & Converter with 30+ common bonds and unit conversion between kJ/mol, kcal/mol, J, and eV, with full step-by-step working and diagrams.
Calorimetry Final Temperature Solver
Find the equilibrium temperature when two substances exchange heat using mA·cA·(Tf − TA) + mB·cB·(Tf − TB) = 0, or solve for an unknown specific heat, mass, or starting temperature, or switch to Advanced Tools to bring a calorimeter constant into the calculation, with full step-by-step working and diagrams.
Equilibrium Constant (Keq) from Gibbs Free Energy
Solve ΔG° = −RT ln K for the equilibrium constant K, the standard free energy ΔG°, or temperature, with instant spontaneity and reaction-extent interpretation, or switch to Advanced Tools to convert between Kp and Kc for gas-phase equilibria, with full step-by-step working and diagrams.
van 't Hoff Equation Solver
Solve the two-point van 't Hoff equation ln(K2/K1) = −(ΔH°/R)(1/T2 − 1/T1) for K2, K1, ΔH°, T1, or T2, with instant endothermic/exothermic interpretation, or switch to Advanced Tools to fit a full van 't Hoff plot (ΔH° and ΔS° from ln K vs 1/T) across any number of data points, with full step-by-step working and diagrams.
Lattice Energy & Born-Haber Cycle
Solve any step of the Born-Haber cycle (sublimation, ionization energy, bond dissociation, electron affinity, lattice energy, enthalpy of formation) with full working and a waterfall cycle diagram, or switch to the Born-Landé equation to predict lattice energy from ionic charge, radius, and the Madelung constant, with a theoretical-vs-experimental comparison chart.
Heat of Combustion Calculator
Find the molar and specific heat of combustion from bomb calorimetry data (Q = CΔT), or switch to Advanced Tools to calculate ΔH°comb for any CxHyOz fuel from standard enthalpies of formation via Hess's Law, with Higher vs Lower Heating Value and a fuel energy-density comparison chart, with full step-by-step working and diagrams.
Chemistry → Chemical Kinetics & Catalysis
Zero-Order Reaction Rate Calculator
Solve the zero-order integrated rate law [A]t = [A]0 − kt for the concentration remaining, the initial concentration, the rate constant k, or the time elapsed, with automatic half-life and time-to-completion — plus an Advanced Tools fit that finds k and [A]0 directly from a table of lab data, with full step-by-step working.
First-Order Reaction Rate Calculator
Solve the first-order integrated rate law [A]t = [A]0 · e^(−kt) for the concentration remaining, the initial concentration, the rate constant k, or the time elapsed, with a constant half-life that doesn't depend on starting concentration — plus an Advanced Tools ln[A]-vs-time fit that finds k and [A]0 directly from a table of lab data, with full step-by-step working.
Second-Order Reaction Rate Calculator
Solve the second-order integrated rate law 1/[A]t = 1/[A]0 + kt for the concentration remaining, the initial concentration, the rate constant k, or the time elapsed, with a half-life that depends on starting concentration and doubles with each successive half-life — plus an Advanced Tools 1/[A]-vs-time fit that finds k and [A]0 directly from a table of lab data, with full step-by-step working.
Arrhenius Activation Energy Solver
Solve the two-point Arrhenius equation ln(k2/k1) = −(Ea/R)(1/T2 − 1/T1) for a new rate constant, the original rate constant, the activation energy Ea, or either temperature, with an instant read on how much faster the reaction runs — plus an Advanced Tools Arrhenius plot that fits Ea and the pre-exponential factor A directly from a table of lab data, with full step-by-step working.
Reaction Rate Constant Calculator
Solve the general rate law rate = k[A]^m[B]^n for the rate constant k, the reaction rate, or a reactant concentration at any reaction order, with automatic unit handling for k — plus an Advanced Tools method of initial rates solver that fits the reaction orders and k directly from a table of lab experiments, with full step-by-step working.
Half-Life Kinetics Calculator
Solve for half-life (t½), the rate constant k, or the initial concentration [A]0 for zero-order, first-order, or second-order reactions, with a chart of how each successive half-life changes (or stays constant) by order — plus an Advanced Tools fractional-life solver that finds the time to reach any percent remaining, with full step-by-step working.
Enzyme Kinetics (Michaelis-Menten)
Solve the Michaelis-Menten equation v = Vmax[S]/(Km + [S]) for reaction velocity, substrate concentration, Km, or Vmax, with a saturation-curve diagram — plus an Advanced Tools Lineweaver-Burk fit from lab data and competitive, uncompetitive, and noncompetitive inhibition modeling, with full step-by-step working.
Turnover Number (kcat) & Catalytic Efficiency
Solve kcat = Vmax / [E]T for turnover number, maximum velocity, or total enzyme concentration, then calculate catalytic efficiency (kcat/Km) in M⁻¹s⁻¹ and see how it compares to the diffusion limit — or switch to Advanced Tools to rank several enzymes side by side on a catalytic-efficiency chart, with full step-by-step working.
Temperature Coefficient (Q10) Calculator
Calculate the Q10 temperature coefficient Q10 = (R2/R1)^[10/(T2−T1)] from two rates measured at two temperatures, predict a new reaction rate, growth rate, or metabolic rate at a target temperature from a known Q10, or solve for the missing temperature — plus an Advanced Tools mode that scales a process duration (incubation, fermentation, cooking time) up or down for a new temperature, with a full temperature-vs-duration table and step-by-step working.
Chemistry → Colligative Properties & Electrochemistry
Boiling Point Elevation Calculator
Calculate boiling point elevation (ΔTb = i × Kb × m), or solve backwards for molality, the van't Hoff factor, an unknown solvent's ebullioscopic constant, or an unknown solute's molar mass from measured lab data, with a solvent preset library and full step-by-step working.
Freezing Point Depression Calculator
Calculate freezing point depression (ΔTf = i × Kf × m), or solve backwards for molality, the van't Hoff factor, an unknown solvent's cryoscopic constant, or an unknown solute's molar mass from measured lab data, with a solvent preset library and full step-by-step working.
Osmotic Pressure Calculator
Calculate osmotic pressure using the van't Hoff equation (π = iMRT) from molarity or solute mass, choose from seven pressure units (atm, kPa, mmHg, torr, bar, psi, Pa), check tonicity against blood plasma, or work backwards from a measured osmotic pressure to find an unknown molar mass, with full step-by-step working.
Raoult's Law & Vapor Pressure Solver
Find vapor pressure lowering for a nonvolatile solute using Raoult's Law, or solve an ideal binary solution of two volatile liquids for the total and partial vapor pressures and vapor-phase composition, with a positive/negative deviation check against a measured pressure, and full step-by-step working.
van 't Hoff Factor Calculator
Calculate the ideal van't Hoff factor (i) from a solute's formula and percent dissociation, or back-calculate the real i from freezing point depression, boiling point elevation, osmotic pressure, or vapor pressure lowering data — plus an advanced tool for finding percent dissociation from a measured i, with full step-by-step working.
Clausius-Clapeyron Vapor Pressure
Solve the Clausius-Clapeyron equation to find a substance's enthalpy of vaporization from two vapor-pressure readings, predict its vapor pressure at a new temperature, or solve for the temperature — including the normal boiling point — at a target pressure, with full step-by-step working.
Nernst Equation Cell Potential
Calculate the non-standard cell potential (E) from E°, moles of electrons transferred (n), temperature, and the reaction quotient (Q), with a live concentration-to-Q builder, a standard reduction potential reference table, E vs log(Q) sensitivity chart, and full step-by-step working.
Standard Cell Potential Calculator
Coming soon: Standard Cell Potential Calculator.
Faraday's Law of Electrolysis
Find the mass deposited or liberated at an electrode, the time needed to electroplate a target mass, or the current efficiency of an electrolysis cell, using Faraday's Laws of Electrolysis, with a built-in library of common metals and gases and full step-by-step working.
Battery Specific Capacity Calculator
Find the theoretical specific capacity of an electrode material from Faraday's Law, calculate the measured specific capacity from real discharge test data with C-rate, or find specific energy and energy density, with a built-in library of common electrode materials and full step-by-step working.
Corrosion Rate Solver
Calculate metal corrosion rate from coupon weight-loss test data (ASTM G1) or from a measured corrosion current density (ASTM G102), with an automatic severity rating and results in mpy, mm/yr, µm/yr, and ipy — plus a Remaining Wall Thickness & Service Life mode that estimates years left before a pipe or tank drops below its minimum safe thickness, with full step-by-step working.
Ionic Conductivity & Molar Conductance
Find specific conductivity from a cell constant and measured resistance, convert it into molar or equivalent conductivity at a known concentration, or apply Kohlrausch's Law to find the limiting molar conductivity, degree of dissociation, and dissociation constant (Ka via Ostwald's Dilution Law) of a weak electrolyte — with built-in ion and electrolyte presets and full step-by-step working.
Cyclic Voltammetry Peak Current
Calculate the peak current of a reversible, diffusion-controlled redox reaction using the Randles-Ševčík equation, or solve backwards for the diffusion coefficient, bulk concentration, scan rate, or number of electrons transferred from a measured peak current, plus a reversibility checker for peak separation and the ipa/ipc ratio, with a live Randles-Ševčík plot and full step-by-step working.
Chemistry → Biochemistry, Clinical & Medical Chemistry
Blood Alcohol Concentration (BAC) Calculator
Estimate your Blood Alcohol Concentration from your drinks, weight, and time using the Widmark formula, with impairment stage and sober-up time.
Anion Gap & Serum Osmolar Gap Solver
Calculate the anion gap (with albumin correction) and serum osmolar gap from your basic metabolic panel, with instant interpretation.
Protein Mass & Peptide Molecular Weight
Calculate the average and monoisotopic molecular weight of any peptide or protein from its amino acid sequence, estimate its UV extinction coefficient and back out concentration from an A280 reading, and convert freely between mass, volume and molar concentration for dosing, dilution and reconstitution, with an amino acid composition chart and complete step-by-step working.
DNA / RNA Concentration & Yield Solver
Calculate DNA or RNA concentration from an A260 reading with automatic dsDNA/ssDNA/RNA conversion factors, check A260/A280 and A260/A230 purity ratios, work out total yield and molar concentration, find copy number for qPCR, and build a full dilution series for a qPCR standard curve, with complete step-by-step working.
Oligonucleotide Melting Temperature
Estimate primer/probe melting temperature (Tm) from a DNA or RNA sequence using the Wallace rule, the %GC method, and full nearest-neighbor thermodynamics (SantaLucia 1998), with a salt-corrected result and complete step-by-step working.
Resuscitation Fluid / Electrolyte Deficit
Calculate maintenance IV fluid rate (Holliday-Segar), fluid deficit from % dehydration, sodium and potassium deficits, an emergency resuscitation bolus, and a full 24-hour replacement schedule, with complete step-by-step working.
Blood pH & Henderson-Hasselbalch Blood Gas
Calculate blood pH from PaCO2 and HCO3 using the Henderson-Hasselbalch equation, identify respiratory or metabolic acidosis/alkalosis, and check compensation with Winter's formula and standard ABG rules.
Ligand Binding Kinetics & Dissociation (Kd)
Find the dissociation constant (Kd) from kon and koff or enter it directly, calculate equilibrium occupancy and bound fraction for any free ligand concentration, model association kinetics (kobs, half-time to equilibrium) with a binding curve, and work out dissociation half-life and residence time after washout, with full step-by-step working.
Isothermal Titration Calorimetry (ITC) Solver
Find Ka, Kd, ΔG and ΔS from a measured ΔH and temperature, check the Wiseman c-value to see whether a planned ITC experiment will give a well-shaped binding curve (with a reverse lookup for the ideal cell concentration), and simulate a single-site Wiseman binding isotherm with cumulative heat per injection, with full step-by-step working and a binding curve chart.
Enzyme Inhibition (Ki) Solver
Convert IC50 to the true inhibition constant Ki with the Cheng-Prusoff equation (and back again), solve for Ki from a single inhibited velocity reading with apparent Km'/Vmax', and calculate percent inhibition or a full IC50 dose-response curve — for competitive, noncompetitive, and uncompetitive inhibitors, with full step-by-step working.
SDS-PAGE Protein Migration Distance
Calculate relative mobility (Rf) from migration distance, build a log(MW) vs Rf calibration curve from your marker standards to estimate an unknown protein's molecular weight (or predict migration distance from a known MW), and get a resolving-gel percentage recommendation, with full step-by-step working and a calibration curve chart.
Chemistry → Environmental, Water & Agricultural Chemistry
Water Hardness Calculator
Find total water hardness as CaCO3 from calcium and magnesium levels or a lab EDTA titration, convert instantly between mg/L, grains per gallon, °dH, °fH and °Clark, and estimate lime-soda softening chemical doses, with a hardness scale chart and complete step-by-step working.
Total Alkalinity & Langelier Index (LSI)
Find total alkalinity as CaCO3 from an acid titration or from bicarbonate, carbonate and hydroxide levels, then calculate the Langelier Saturation Index (LSI) from pH, temperature, calcium hardness, alkalinity and TDS to see if water is corrosive, balanced, or scale-forming, with a saturation index scale chart and complete step-by-step working.
Sodium Adsorption Ratio (SAR) for Soil
Find the Sodium Adsorption Ratio (SAR) of soil or irrigation water from sodium, calcium and magnesium in mg/L or meq/L, get the USSL sodium-hazard class (S1-S4), and — with optional inputs — the salinity hazard, residual sodium carbonate (RSC), sodium percentage, magnesium hazard ratio, permeability index and Kelly's ratio, with a sodium-hazard scale chart and complete step-by-step working.
TDS to Electrical Conductivity (EC) Converter
Convert Total Dissolved Solids (TDS) to Electrical Conductivity (EC) or the other way round, in mg/L, g/L, µS/cm, mS/cm or dS/m, choose from standard conversion factors (0.5, 0.55, 0.64, 0.7) or enter your own, compensate for temperature, and get instant drinking-water quality and irrigation salinity-hazard classification with a TDS scale chart and complete step-by-step working.
Biological Oxygen Demand (BOD) Calculator
Calculate BOD5 from a standard dilution or seeded lab test, work out BOD mass load, removal efficiency and population equivalent for a wastewater treatment plant, or find the ultimate BOD using first-order kinetics, with a water quality scale, exertion curve, and complete step-by-step working.
Chemical Oxygen Demand (COD) Calculator
Calculate COD from a standard dichromate reflux titration test, work out COD mass load, removal efficiency and population equivalent for a wastewater treatment plant, or find the BOD5/COD biodegradability ratio, with a water quality scale, comparison chart, and complete step-by-step working.
Soil Fertilizer NPK Ratio & Mass Calculator
Simplify any fertilizer's N-P2O5-K2O grade into its true NPK ratio with total nutrient content and elemental P/K conversion, work out exactly how many kilograms of fertilizer to apply per acre or hectare, or split a nutrient target across urea, DAP and MOP, with charts and complete step-by-step working.
Chlorine Dosing & Residual Water Disinfection
Work out the exact chlorine dose needed for your water's demand and target residual, convert that dose into a real feed rate for liquid bleach, HTH granules or chlorine gas, check your CT value against disinfection log-inactivation credit, or predict how a free chlorine residual decays over time, with charts and complete step-by-step working.
Heavy Metal Concentration Index in Water
Enter measured concentrations for arsenic, lead, cadmium, chromium, mercury and more, and instantly get the Heavy Metal Pollution Index (HPI), Heavy Metal Evaluation Index (HEI), Degree of Contamination (Cd), and Nemerow Pollution Index (NPI) together, with built-in WHO and BIS 10500 permissible limits, a per-metal contamination chart, and complete step-by-step working.
Chemistry → Food, Beverage, Brewing & Petroleum Chemistry
Alcohol by Volume (ABV) & Proof Calculator
Calculate alcohol by volume from gravity readings, convert ABV to proof, and work out standard drinks, calories, dilution, and blending.
Brix to Specific Gravity / Plato Converter
Convert Brix or Plato readings to specific gravity, convert SG back to Brix/Plato, and correct a post-fermentation refractometer reading for alcohol interference using the Sean Terrill formula, with Baumé, apparent attenuation, and estimated ABV included.
Titratable Acidity Calculator (Wine/Juice)
Calculate titratable acidity (TA) from titration data for wine, juice, cider, and vinegar — in g/L, percent acid, and mEq/L — with tartaric, citric, malic, acetic, and lactic acid presets, a titer/normalization factor, instant cross-acid conversions, and a Brix:TA ripeness ratio tool.
API Gravity & Crude Oil Density Calculator
Convert API gravity to specific gravity and density (kg/m³, g/cm³, lb/ft³, lb/gal), classify crude oil as light, medium, heavy, or extra heavy, and convert barrels to metric tons using common crude oil benchmarks like WTI and Brent.
Polymer Polydispersity Index (PDI) Calculator
Find the polydispersity index (PDI / Đ = Mw/Mn) directly from Mn and Mw, compute Mn, Mw and Mz from a full chain-length distribution table, solve the Mn/Mw/PDI triangle for a missing value, and find the degree of polymerization — with instant narrow-to-broad classification.
Polymer Glass Transition Temperature Estimator
Estimate the glass transition temperature (Tg) of a polymer blend or copolymer with the Fox equation for any number of components, or the Gordon-Taylor equation for two-component blends, find how molecular weight lowers Tg with the Flory-Fox equation, and look up Tg for 15+ common polymers.
Saponification Value & Soap Lye Calculator
Build a cold-process or hot-process soap recipe from 16 built-in oils and butters, get exact NaOH or KOH and water amounts with a superfat allowance and a soap-quality breakdown, or calculate a fat's saponification value from titration data.
Chemistry → Organic, Spectroscopy & Materials Science
Degree of Unsaturation / DBE Calculator
Find the degree of unsaturation (DBE, or index of hydrogen deficiency) of any molecular formula, or straight from manual atom counts, with a plain-language explanation, possible ring/double/triple bond combinations, and full step-by-step working.
Chiral Specific Rotation & Optical Purity
Calculate specific rotation from observed rotation, path length and concentration — or solve for any of the four — and find optical purity, enantiomeric excess (ee%), and the true enantiomer split, with a built-in library of common chiral compounds and full step-by-step working.
Thin Layer Chromatography Rf Factor Calculator
Calculate the Rf (retention factor) of one or more TLC spots from the distance travelled by the compound and the solvent front, or solve for the spot or solvent-front distance instead, with relative Rf (Rx) against a reference spot, a scaled plate diagram, and full step-by-step working.
Solvent Polarity Index & Blend Miscibility
Look up the Snyder polarity index (P') and dielectric constant for 20+ common solvents, blend any two by volume ratio to find the resulting polarity and dielectric constant, and get an instant miscibility verdict, with a polarity scale diagram and full step-by-step working.
Beer-Lambert Law Spectrophotometry
Solve the Beer-Lambert Law (A = ε·l·c) for absorbance, molar absorptivity, path length, or concentration, convert freely between absorbance and %transmittance, and find an unknown sample's concentration from a calibration curve of standards — with a built-in library of common chromophores, a linearity chart, and full step-by-step working.
HPLC Column Resolution & Capacity Factor
Calculate HPLC capacity factor (k′) from retention time and dead time, resolution (Rs) between two peaks from retention times and peak widths, the selectivity factor (α), theoretical plate count (N) and plate height (H), or solve the fundamental resolution equation — with a chromatogram diagram and full step-by-step working.
Construction
Construction → Construction Converters
Board Foot Calculator
Convert lumber dimensions into board feet for pricing and ordering.
Cubic Yard Calculator
Convert length, width, and depth into cubic yards for material orders.
Gallons per Square Foot Calculator
Convert a coverage rate into gallons needed per square foot of area.
Size to Weight Calculator (Rectangular Box)
Estimate the weight of a rectangular box from its dimensions and material.
Square Feet to Cubic Yards Calculator
Convert a square footage and depth into cubic yards of material.
Square Footage Calculator
Calculate the square footage of a room or area from its dimensions.
Square Yards Calculator
Convert an area into square yards for flooring or landscaping estimates.
Square Feet to Acres Calculator
Convert a lot or land area in square feet into acres.
Construction → Construction Materials Calculators
Aluminum Weight Calculator
Estimate the weight of aluminum stock from its shape and dimensions.
Baluster Calculator
Work out how many balusters you need and their spacing for a railing.
Board and Batten Calculator
Calculate boards, battens, and spacing needed for a board-and-batten wall.
Brick Calculator
Estimate the number of bricks and mortar needed for a wall or project.
Decking Calculator
Calculate decking boards, spacing, and material needed for a deck.
DIY Shed Cost Calculator
Estimate the total material cost of building a shed yourself.
Drywall Calculator
Calculate the number of drywall sheets needed for walls and ceilings.
Fire Glass Calculator
Estimate how much fire glass you need to fill a fire pit or feature.
Framing Calculator
Calculate studs, plates, and spacing needed to frame a wall.
French Drain Calculator
Estimate pipe, gravel, and fabric needed to install a French drain.
Glass Weight Calculator
Estimate the weight of a glass pane from its size and thickness.
Gravel Calculator
Calculate how much gravel you need by area, depth, and coverage.
Landscape Rock Calculator
Estimate the tonnage of landscape rock needed to cover an area.
Limestone Calculator
Calculate the amount of limestone needed by area, depth, and density.
Log Weight Calculator
Estimate the weight of a log from its species, length, and diameter.
Lumber Calculator
Calculate the amount and cost of lumber needed for a project.
Metal Weight Calculator
Estimate the weight of metal stock from its shape, size, and alloy.
Pipe Weight Calculator
Estimate the weight of a pipe from its diameter, thickness, and material.
Plate Weight Calculator
Estimate the weight of a metal plate from its dimensions and material.
Quiz: Pipe Weight Calculator
Test your knowledge of how pipe weight is calculated.
Quiz: Stone Calculator
Test your knowledge of how stone and gravel quantities are calculated.
Rebar Calculator
Estimate the amount of rebar needed to reinforce a concrete slab.
Retaining Wall Calculator
Estimate blocks, base material, and cost for a retaining wall.
Rip Rap Calculator
Calculate the amount of rip rap needed for erosion control.
River Rock Calculator
Estimate the tonnage of river rock needed to cover an area.
Rolling Offset Calculator
Calculate pipe length and angles needed for a rolling offset.
SAG Calculator
Calculate cable or beam sag between two support points.
Sand Calculator
Calculate how much sand you need by area, depth, and coverage.
Sealant Calculator
Estimate how much sealant you need for a given joint length.
Sonotube Calculator
Calculate the concrete volume needed to fill a sonotube form.
Spindle Spacing Calculator
Work out even spindle spacing and count for a railing run.
Spiral Staircase Calculator
Calculate rise, run, and rotation for a spiral staircase.
Steel Plate Weight Calculator
Estimate the weight of a steel plate from its dimensions.
Steel Weight Calculator
Estimate the weight of steel stock from its shape and dimensions.
Stone Weight Calculator
Estimate the weight of stone from its volume and density.
Tile Calculator
Calculate the number of tiles and boxes needed for a floor or wall.
Tonnage Calculator
Convert a material volume into tons based on its density.
Vinyl Fence Calculator
Estimate panels, posts, and material needed for a vinyl fence.
Vinyl Siding Calculator
Calculate the amount of vinyl siding needed to cover exterior walls.
Wall Square Footage Calculator
Calculate the total square footage of a wall for material estimates.
Gutter Calculator
Calculate the length of gutters and downspouts needed for a roofline.
Stucco Calculator
Estimate the amount of stucco needed to cover exterior walls.
Excavation Calculator
Estimate the volume of soil to excavate for a foundation or trench.
Construction → Cement and Concrete Calculators
Cement Calculator
Calculate how many bags of cement you need for a project.
Concrete Calculator
Calculate the volume of concrete needed for a slab, footing, or wall.
Concrete Block Calculator
Estimate the number of concrete blocks needed for a wall.
Concrete Block Fill Calculator
Calculate the grout needed to fill hollow concrete blocks.
Concrete Column Calculator
Calculate the concrete volume needed to pour a column.
Concrete Stairs Calculator
Estimate the concrete volume needed to pour a staircase.
Concrete Estimator - Tube
Estimate concrete volume needed to fill cylindrical tube forms.
Concrete Weight Calculator
Estimate the weight of a poured concrete slab or structure.
Grout Calculator
Calculate how much grout you need for a tile installation.
Hole Volume Calculator
Calculate the concrete volume needed to fill a post or footing hole.
Mortar Calculator
Estimate how much mortar you need for brick or block work.
Thinset Calculator
Calculate how much thinset mortar you need for a tile job.
Construction → Home and Garden Calculators
AC Tonnage Calculator
Estimate the air conditioning tonnage needed for a space.
Air Changes per Hour Calculator
Calculate how many times per hour a room's air is replaced.
Air Conditioner BTU Calculator
Estimate the BTU output needed to cool a room properly.
Arch Calculator
Calculate the radius and dimensions needed to build an arch.
Boiler Size Calculator
Estimate the boiler size needed to heat your home.
Carpet Calculator
Calculate the amount of carpet and padding needed for a room.
Chicken Coop Size Calculator
Work out the coop and run size needed for your flock.
Clearance Hole Calculator
Find the correct clearance hole size for a given bolt or screw.
Deck Stain Calculator
Estimate how much deck stain you need for a given deck size.
Epoxy Calculator
Calculate how much epoxy resin you need to cover a surface.
Fence Calculator
Estimate posts, panels, and material needed for a fence.
Rectangle Fence Perimeter Calculator
Calculate the perimeter and material needed for a rectangular fence.
Fence Post Depth Calculator
Work out how deep to set fence posts based on height and soil.
Floor Area Ratio Calculator
Calculate a building's floor area ratio from lot and floor size.
Flooring Calculator
Estimate how much flooring material you need for a room.
Furnace Size Calculator
Estimate the furnace size needed to heat your home.
Heat Loss Calculator
Estimate a building's heat loss to size heating equipment.
Hoop House Calculator
Calculate materials and dimensions needed to build a hoop house.
Ladder Angle Calculator
Find the safe angle and base distance for ladder placement.
Paint Calculator
Estimate how many gallons of paint you need for a room.
Paver Calculator
Calculate the number of pavers needed to cover a patio or path.
Paver Sand Calculator
Estimate the bedding sand needed under a paver installation.
Plywood Calculator
Calculate the number of plywood sheets needed for a project.
Ramp Calculator
Calculate the length and slope needed for an accessible ramp.
Shiplap Calculator
Estimate the shiplap boards needed to cover a wall or ceiling.
Siding Calculator
Estimate the amount of siding needed to cover exterior walls.
Square Yard Calculator
Convert an area into square yards for flooring or turf estimates.
Stair Carpet Calculator
Estimate the carpet needed to cover a staircase.
Stair Calculator
Calculate rise, run, and step count for a staircase.
Wainscoting Calculator
Estimate the panels and material needed for wainscoting.
Wallpaper Calculator
Calculate the number of wallpaper rolls needed for a room.
Construction → Roofing Calculators
Birdsmouth Cut Calculator
Calculate the birdsmouth notch dimensions for a rafter.
Gambrel Roof Calculator
Calculate rafter lengths and angles for a gambrel roof.
Metal Roof Cost Calculator
Estimate the material and installation cost of a metal roof.
Rafter Length Calculator
Calculate the rafter length needed for a given roof pitch and span.
Roofing Calculator
Estimate roofing material, squares, and cost for a roof.
Roof Pitch Calculator
Calculate roof pitch, angle, and slope from rise and run.
Roof Shingle Calculator
Estimate the number of shingle bundles needed for a roof.
Roof Truss Calculator
Calculate truss dimensions and spacing for a roof.
Snow Load Calculator
Estimate the snow load a roof structure needs to support.
Construction → Driveway Calculators
Asphalt Calculator
Calculate the tonnage of asphalt needed for a driveway or lot.
Concrete Driveway Cost Calculator
Estimate the material cost of pouring a concrete driveway.
Crushed Stone Calculator
Calculate the amount of crushed stone needed for a base or path.
Gravel Driveway Calculator
Estimate the gravel needed to build or resurface a driveway.
Road Base Calculator
Calculate the base material needed for a road or driveway.
Construction → Water Tank and Vessels Calculators
Fire Flow Calculator
Estimate the water flow rate needed for fire suppression.
Gallons Per Minute Calculator (GPM)
Calculate flow rate in gallons per minute from volume and time.
Liters per Minute Calculator
Calculate flow rate in liters per minute from volume and time.
Pipe Volume Calculator
Calculate the internal volume of a pipe from its dimensions.
Pond Calculator
Estimate the water volume of a pond from its dimensions.
Pool Calculator
Calculate the water volume of a swimming pool.
Round Pool Volume Calculator
Calculate the water volume of a round or circular pool.
Tank Volume Calculator
Calculate the volume and capacity of a storage tank.
Construction → Materials Specifications Calculators
Beam Deflection Calculator
Estimate how much a beam will deflect under a given load.
Beam Load Calculator
Calculate the maximum load a beam can safely support.
Bending Stress Calculator
Calculate the bending stress on a beam under load.
Bolt Torque Calculator
Calculate the correct tightening torque for a bolt.
Box Fill Calculator
Calculate the minimum electrical box size for a given wire count.
Carbon Equivalent Calculator
Calculate the carbon equivalent value of a steel alloy for weldability.
CFM Calculator
Calculate airflow in cubic feet per minute for ventilation sizing.
Door Header Size Calculator
Calculate the header size needed to span a door opening.
Floor Joist Calculator
Calculate joist size and spacing needed for a floor span.
Insulation Calculator
Estimate the insulation material needed for a given R-value and area.
Junction Box Sizing Calculator
Calculate the correct junction box size for a wiring job.
K-Factor Calculator
Calculate the K-factor used for sheet metal bend allowances.
Material Removal Rate Calculator
Calculate the material removal rate for a machining operation.
Pitch Diameter Calculator
Calculate the pitch diameter of a gear or threaded part.
Punch Force Calculator
Estimate the force needed to punch through a given material.
Quiz: Beam Load Calculator
Test your knowledge of how beam load capacity is calculated.
Rivet Size Calculator
Find the correct rivet size and length for a given joint.
Spindle Speed Calculator
Calculate the correct spindle speed for a machining operation.
Taper Calculator
Calculate taper angle, diameter, and length for a tapered part.
Thread Calculator
Calculate thread dimensions for a given screw or bolt size.
Thread Pitch Calculator
Calculate thread pitch from diameter and threads per inch.
True Position Calculator
Calculate the true position tolerance for a machined feature.
Welding Calculator
Estimate welding rod, wire, or time needed for a weld job.
Wood Beam Span Calculator
Calculate the maximum span for a wood beam under a given load.
Construction → Landscaping Calculators
Mulch Calculator
Calculate how many bags or yards of mulch you need for a garden bed.
Topsoil Calculator
Calculate how much topsoil you need to cover an area.
Sod Calculator
Calculate how many pieces or pallets of sod you need for a lawn.
Grass Seed Calculator
Calculate how much grass seed you need to cover a lawn area.
Fill Dirt Calculator
Calculate how much fill dirt you need for grading or leveling.
Construction → Cost Estimators
Cost to Build a House Calculator
Estimate the total cost of building a new house.
Home Renovation Cost Calculator
Estimate the cost of a home renovation project.
Concrete Cost Calculator
Estimate the total material and labor cost of a concrete pour.
Roofing Cost Calculator
Estimate the total cost of a roofing project.
Fence Cost Calculator
Estimate the total material and labor cost of building a fence.
Deck Cost Calculator
Estimate the total material and labor cost of building a deck.
Flooring Cost Calculator
Estimate the total cost of flooring materials and installation.
Painting Cost Calculator
Estimate the total cost of painting a room or exterior.
Patio Cost Calculator
Estimate the total cost of building a patio.
Construction → Other Calculators
Angle Cut Calculator
Calculate the angle and length needed for a compound cut.
Angle of Depression Calculator
Calculate the angle of depression between two points.
Bolt Circle Calculator
Calculate hole positions evenly spaced around a bolt circle.
Bowl Segment Calculator
Calculate segment angles and dimensions for a segmented bowl.
Countersink Depth Calculator
Calculate the correct countersink depth for a given screw.
Elevation Grade Calculator
Calculate slope grade percentage from rise and run.
Miter Angle Calculator
Calculate the miter angle needed to join two pieces at a corner.
Round Pen Calculator
Calculate fencing material needed for a round training pen.
Trump's Wall Calculator
A novelty calculator estimating material and cost for a border wall.
Vertical Curve Calculator
Calculate elevation points along a vertical roadway curve.
Sports
Cricket Run Rate Calculator
Calculate current run rate (CRR) and required run rate (RRR) for any cricket run chase.
Cricket NRR Calculator
Calculate Net Run Rate (NRR) the same way IPL and ICC tournament points tables do.
Cricket Strike Rate & Batting Average Calculator
Calculate batting strike rate and batting average from runs, balls faced, and dismissals.
Fantasy Cricket Points Calculator
Estimate fantasy cricket points from batting, bowling, and fielding stats for T20, ODI, and Test.
Football Fantasy Points Calculator
Estimate fantasy football (soccer) points from goals, assists, clean sheets, cards, and saves.
Betting Odds Calculator
Convert betting odds between decimal, fractional, and American formats and see potential payout.
Entertainment
Entertainment → Love & Relationship
Name Love Compatibility Meter
Enter two names to get a fun love compatibility percentage.
FLAMES Calculator
Classic FLAMES (Friends, Lovers, Affection, Marriage, Enemies, Siblings) name game.
Zodiac / Horoscope Match
Match two zodiac signs and get a fun love compatibility score.
Love Meter with Quiz
Answer a few fun questions to test your bonding strength as a couple.
Couple Nickname Generator
Blend two names together into cute couple nickname suggestions.
Red Flag vs Green Flag Meter
Pick your partner's habits and get a fun relationship health score.
Anniversary / Love Duration Counter
Live counter showing exactly how many days, hours, and minutes you've been together.
Love Future Predictor
Fun predictor for your future wedding date or dream travel destination.
Entertainment → Friendship & Squad
Bestie Quiz / Friendship Test
Create a custom 10-question quiz to test and share with your friends.
Friendship Percentage Meter
Enter names and birthdays to get a fun friendship compatibility score.
Squad Role Assigner
Enter your friend group's names and get assigned roles like Leader, Planner, and Joker.
Group Vibe / Synergy Meter
Enter 3-5 friends' names to get your group's overall vibe score.
Who Knows Me Better? (Duo Challenge)
Live quiz between two friends with real-time point tallying.
Toxic / Loyalty Meter
Fun test to see how loyal (or not) your friend really is.
Slam Book
Pick fun questions, pick a diary theme, and get a link every friend can fill, download, and share.
Entertainment → Interactive & Group Games
TDS — Truth Dare Situation Game
Random truth, dare, and situation tasks with Couple, Friendship, and Party modes.
Digital Spin the Bottle
Spin a virtual bottle on screen to decide whose turn is next.
Never Have I Ever
Card-based Never Have I Ever game with Couple and Friends editions and scoring.
Would You Rather?
Fun dilemmas with tricky options to choose between.
Secret Crush Predictor
Fun shareable link to prank friends with a secret crush prediction.
Most Likely To...
Group game where a situation appears on screen and everyone picks who fits it best.