All calculators

Every calculator on the site, grouped by category. Each one runs in your browser and explains how its answer is worked out.

Looking for text, developer or generator tools? Browse all tools.

Everyday Maths

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Basic Calculator

Add, subtract, multiply and divide with brackets, percentages and full keyboard support.

Percentage Calculator

Find P% of a number, what percent one number is of another, or the total from a percentage.

Percentage Change Calculator

Calculate the percentage increase or decrease between an original and a new value.

Discount Calculator

Find the sale price and savings from a percentage or fixed discount, with optional sales tax.

Average Calculator

Calculate the mean, sum, count, median, minimum and maximum of a list of numbers.

Ratio Calculator

Simplify ratios and solve proportions A : B = C : D for a missing value.

Fraction Calculator

Add, subtract, multiply and divide fractions and mixed numbers with simplified answers.

Unit Price Calculator

Compare prices per kg, litre or item to find the best-value pack.

Electricity Cost Calculator

Estimate how much your appliances cost to run per day, month and year.

Numbers, Algebra and Statistics

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Scientific Calculator

Trigonometry, logarithms, powers, roots, factorials and constants in degrees or radians.

Standard Deviation Calculator

Sample and population standard deviation, variance, mean and standard error from a list of numbers.

LCM and GCF Calculator

Find the least common multiple and greatest common factor of two or more whole numbers.

Quadratic Equation Solver

Solve ax² + bx + c = 0 for real or complex roots, with the discriminant and vertex.

Prime Factorization Calculator

Check whether a number is prime and break it into prime factors, with all its divisors.

Number Base Converter

Convert whole numbers between binary, octal, decimal, hexadecimal and any base from 2 to 36.

Roman Numeral Converter

Convert numbers to Roman numerals and back, from 1 to 3,999, with a symbol breakdown.

Rounding Calculator

Round to decimal places, significant figures or the nearest multiple, with five rounding rules.

Scientific Notation Converter

Convert numbers to and from scientific, E and engineering notation, with significant figures.

Random Number Generator

Generate random whole numbers or decimals in any range, with or without repeats.

Permutation and Combination Calculator

Calculate nPr and nCr exactly, with and without repetition.

Probability Calculator

Probability of two events, at least once in n tries, and binomial outcomes.

Matrix Calculator

Determinant, inverse, transpose, multiplication, addition and powers of matrices.

System of Equations Solver

Solve systems of linear equations like 2x + 3y = 8, with up to 8 unknowns.

Percent Error and Significant Figures Calculator

Percent error between measured and true values, and significant figure counting and rounding.

Date and Time

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Age Calculator

Calculate exact age in years, months and days, total days lived and the next birthday.

Date Difference Calculator

Find the time between two dates in years, months and days, plus total days and weeks.

Days Between Dates

Count the days between two dates, optionally including the end date, with weekdays and weekends.

Time Duration Calculator

Calculate hours and minutes between two times, including overnight shifts and breaks.

Add or Subtract Days to a Date

Add or subtract days, weeks, months, years or business days from any date.

Time Zone Converter

Convert a date and time between any two time zones, with daylight saving time handled.

Work Hours Calculator

Total your shifts with breaks and overnight hours, and calculate overtime pay.

Unit Conversions

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Length Converter

Convert between millimeters, centimeters, meters, kilometers, inches, feet, yards and miles.

Weight and Mass Converter

Convert between milligrams, grams, kilograms, tonnes, ounces and pounds.

Temperature Converter

Convert temperatures between Celsius, Fahrenheit and Kelvin with the correct offset formulas.

Volume Converter

Convert milliliters, liters, cubic meters, US and imperial gallons, cups and fluid ounces.

Speed Converter

Convert between meters per second, kilometers per hour, miles per hour and knots.

Data Storage Converter

Convert bits and bytes between decimal KB, MB, GB, TB and binary KiB, MiB, GiB, TiB.

Fuel Cost Calculator

Estimate fuel needed and trip cost from distance, fuel economy and fuel price.

Area Unit Converter

Convert square meters, square feet, acres, hectares, square miles and more.

Pressure Converter

Convert psi, bar, kPa, atm, mmHg, inHg, hPa and pascals.

Energy Converter

Convert joules, kilojoules, calories, kilocalories, kWh, BTU and more.

Cooking Measurement Converter

Convert cups, spoons, grams and ounces for common baking ingredients.

Education

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Grade Calculator

Total your marks across assessments and convert the percentage to a grade using your own boundaries.

GPA Calculator

Calculate a credit-weighted GPA with an editable grading scale and optional cumulative GPA.

Weighted Average Calculator

Calculate an average where each value has its own weight, such as course components.

Final Grade Calculator

Find the score you need on your final exam to reach a target overall grade.

Finance and Shopping

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Compound Interest Calculator

Project savings growth with compounding, regular contributions and a year-by-year breakdown.

Simple Interest Calculator

Calculate simple interest, or solve for the principal, rate or time.

Loan Payment Calculator

Estimate loan repayments, total interest and an amortization schedule for any payment frequency.

Tip Calculator

Work out the tip and split the bill fairly between any number of people.

Sales Tax and VAT Calculator

Add sales tax or VAT to a price, or extract the tax from a tax-inclusive amount.

Mortgage Calculator

Estimate your monthly mortgage payment including tax, insurance, HOA fees and PMI.

Savings Goal Calculator

Find how much to save each month to reach a goal, or how long a monthly deposit will take.

Inflation Calculator

See how prices and purchasing power change with inflation, or find the average inflation rate.

ROI and CAGR Calculator

Calculate return on investment and the compound annual growth rate (CAGR).

Salary and Hourly Wage Calculator

Convert pay between hourly, daily, weekly, monthly and annual amounts.

Profit Margin and Markup Calculator

Calculate profit margin, markup and selling price from cost and price.

Credit Card Payoff Calculator

See how long it takes to clear a card balance and how much interest you will pay.

Retirement Savings Calculator

Project your retirement savings and the income they could provide, in today’s money.

SIP Calculator

Estimate the future value of a monthly SIP, with optional yearly step-up and lump sum.

Rent vs Buy Calculator

Compare the long-run cost of renting and buying a home, including investing the difference.

Break-Even Calculator

Find how many units you must sell to cover costs or hit a profit target.

Debt Payoff Calculator

Compare debt avalanche and snowball plans to see when you will be debt-free.

Health and Fitness

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BMI Calculator

Calculate adult body mass index in metric or imperial units with WHO reference categories.

BMR and TDEE Calculator

Estimate basal metabolic rate and total daily calorie needs with three common equations.

Pace Calculator

Calculate running pace, finish time or distance in kilometers or miles.

Body Fat Calculator

Estimate body fat percentage with the U.S. Navy tape-measure method.

Ideal Weight Calculator

Compare four ideal body weight formulas and the healthy BMI weight range for your height.

Macro Calculator

Split daily calories into grams of protein, carbohydrate and fat.

Pregnancy Due Date Calculator

Estimate a due date from the last period, conception or IVF transfer date.

Target Heart Rate Calculator

Estimate maximum heart rate and five training zones by age, with optional resting heart rate.

Calories Burned Calculator

Estimate calories burned in walking, running, cycling, swimming and 25+ activities.

Water Intake Calculator

Estimate how much water to drink a day based on weight, exercise and climate.

Sleep Calculator

Find bedtimes or wake-up times that line up with 90-minute sleep cycles.

Ovulation Calculator

Estimate your fertile window, ovulation day and next period for the coming cycles.

Geometry

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Area and Geometry Calculator

Calculate area and perimeter of rectangles, squares, triangles and circles.

Volume and Surface Area Calculator

Volume, surface area and capacity of boxes, cubes, cylinders, spheres, cones and pyramids.

Pythagorean Theorem Calculator

Find the missing side of a right triangle, plus its angles, area and perimeter.