All tools
The full list of free calculators, sorted by topic.
Math
- Percentage calculatorWork out X% of a number, a percentage increase or decrease, or a share in %.
- Fraction calculatorAdd, subtract, multiply and divide fractions, simplified automatically.
- Circle calculator: area and circumferenceArea, circumference, radius and diameter of a circle from a single measurement.
- Average calculator (and weighted average)Mean, median and weighted average of a list of numbers.
- Online scientific calculatorType a calculation with sine, roots, logarithms or powers and see the answer at once.
- Simple online calculatorAdd, subtract, multiply, divide and use percentages, with the right order of operations.
- Triangle solver: sides, angles and areaGive three measurements of a triangle and get the other sides, the angles and the area.
- Volume calculator: cube, cylinder, sphere, cone…Volume of a cube, box, cylinder, sphere, hemisphere, cone or pyramid, also in litres.
- Standard deviation and variance calculatorStandard deviation and variance of a list of numbers, for a sample (n − 1) or a population (n).
- Random number generatorDraw one or more random whole numbers between two limits, with or without repeats.
- Arithmetic and geometric sequence calculatorThe n-th term and the sum of the first n terms of an arithmetic or geometric sequence.
- Quadratic equation solverSolve ax² + bx + c = 0: discriminant, real or complex roots.
- Slope of a lineSlope and equation of a line from two points or from ax + by = c.
- Logarithm calculatorLogarithm of a number in base 10, e (ln), 2 or any other base.
- Area calculator for shapesArea of a square, rectangle, triangle, trapezoid, rhombus, ellipse, polygon and more.
- Surface area of solidsSurface area of a cube, box, cylinder, cone, sphere or pyramid, open or closed.
- Sample size calculator (survey)How many people to survey, from the confidence level and the margin of error.
- Probability of two eventsProbability of A and B, A or B, at least one, neither, exactly one, from how A and B are linked.
- Z-score calculator (standard score)Z-score of a value and its position (percentile) on the bell curve.
- LCM calculator (least common multiple)The smallest number that is a multiple of all your numbers, with the steps.
- GCD calculator (greatest common divisor)The largest number that divides all your numbers, with Euclid’s steps.
- Divisors of a numberAll the divisors of a whole number, how many there are, their sum and the pairs.
- Prime factorization calculatorWrite a whole number as a product of prime numbers, with powers.
- Common divisors of several numbersEvery number that divides each of your numbers, and their GCD.
- Percent error calculatorHow far a measurement is from the expected value, in percent, with its sign.
- Exponent calculator (powers)A number to the power n: whole, negative, decimal or fraction exponent.
- Square root, cube root and nth root calculatorThe nth root of a number: square (n = 2), cube (n = 3) or any other, in real or complex mode.
- Binary calculatorAdd, subtract, multiply, divide and AND / OR / XOR in binary, with the decimal value.
- Hexadecimal calculatorAdd, subtract, multiply and divide in base 16, with the decimal and binary values.
- Half-life calculator (radioactive decay)Amount left, time elapsed, half-life or starting amount: find the unknown value.
- Ratio and proportion calculatorFind the missing term of a : b = c : d and simplify a ratio.
- Permutations and combinations (with or without repetition)How many ways to pick r items out of n, when order matters or not. Exact result.
- Long division calculator with stepsQuotient, remainder and every step of the long division, with decimals.
- Rounding calculator (5 rounding modes)Round half up, half to even, down, up or toward zero, to decimals or significant figures.
- Scientific notation converterWrite a number as a × 10ⁿ, in E notation and in engineering notation.
- Big number calculator (exact precision)Add, subtract, multiply or divide numbers hundreds of digits long, with no loss of precision.
- Descriptive statistics calculatorMean, median, quartiles, variance, standard deviation, minimum, maximum and range of a list of numbers.
- Mean, median, mode and range calculatorMean, median, mode (one or several) and range of a data set, with the sorted list.
- Confidence interval calculator (mean or proportion)Confidence interval for a mean (Student t or normal) or a proportion (Wilson).
- Distance between two points (2D or 3D)Straight-line distance between two points in the plane or in space, with the steps and the midpoint.
- Pythagorean theorem calculator: find the missing sideFinds the hypotenuse or a leg of a right triangle from the other two sides.
- Right triangle calculator: sides, angles and areaSolves a right triangle from two sides or a side and an angle: sides, angles, area, perimeter.
- Matrix calculator (up to 4 × 4)Add, subtract, multiply, determinant, inverse and transpose of matrices up to 4 × 4.
- P-value calculator (z, t, chi-square, F)P-value of a z, Student t, chi-square or Fisher F statistic, one- or two-tailed.
Money
- Compound interest calculatorHow much your savings grow when interest also earns interest.
- Loan payment calculatorMonthly payment, total cost and schedule of a fixed-payment loan.
- Simple interest calculatorInterest on money saved or lent, without compounding.
- VAT calculator: add or remove taxGo from a price before tax to a price with tax, or back, using the standard VAT rate for the selected country.
- Discount and sale price calculatorPrice after a discount, with a second discount if needed.
- Mortgage calculatorMonthly payment, total cost and schedule of a home loan.
- Car loan calculatorMonthly payment and cost of a loan to buy a car.
- Boat loan calculatorMonthly payment and cost of a loan to buy a boat.
- Business loan calculatorMonthly payment, cost and schedule of a loan for a business.
- Personal loan calculatorMonthly payment and cost of a personal loan, fees included.
- Student loan calculatorMonthly payment of a student loan with a deferral period.
- Loan payment or term calculatorFind the payment from the length, or the length from the payment.
- Loan amortization scheduleHow much principal and interest you repay each year, and what is left.
- Repayment schedule calculatorThe amount of each payment, how many there are and the date of the last one, at the pace you choose.
- Investment projection calculatorWhat an investment with monthly deposits could grow to, at an assumed return.
- Retirement savings projectionEstimate your savings at retirement and the income they could give you.
- Fund projection with feesSee how much a fund’s fees (mutual fund, ETF) cost you over time.
- 401(k) calculator (US, 2026)Projection of a US 401(k) retirement account with employer match and 2026 limits.
- Roth IRA calculator (US, 2026)Projection of a US Roth IRA with the 2026 limit and income check, compared with a traditional IRA.
- Traditional IRA calculator (US, 2026)Projection of a US traditional IRA with the 2026 limit, before and after tax.
- Income tax calculatorApplies the supplied income-tax brackets for covered countries, or an effective rate where no usable schedule is available.
- Marriage penalty or bonus calculator (US 2026)Compares the 2026 US federal tax of two people filing single or married filing jointly.
- Estate tax estimate (US 2026 or your own rate)A simple estimate of estate tax: 2026 US federal model, or your own allowance and rate.
- Currency converterConvert an amount with the latest available reference rate or a historical rate.
- Inflation and buying power calculatorWhat something that costs an amount today will cost later, and what your money will be worth.
- Salary converter: hourly, monthly, yearlyTurn pay per hour, day, week, month or year into every other period.
- Sales tax calculatorAdd sales tax to a price or take it out, with a state rate and a local rate.
- Margin and markup calculatorWork out profit, markup (on cost) and margin (on selling price).
- Successive discounts calculatorFinal price and real total discount when several discounts stack.
- Property investment analysisPurchase, rent, loan and sale: the gross, net and after-tax gain.
- Gross to net salaryYour take-home pay per year, month, week and hour by country: employee contributions and 2026 income tax.
- Lease payment calculatorThe monthly payment of a finance lease and its total cost.
- Refinance calculatorWhat you really save by changing rate, with fees and length included.
- Personal monthly budgetIncome, spending and savings: what is left at the end of the month.
- Rental property return calculatorGross yield, net yield and cash flow of a home you rent out.
- FHA loan calculator (US, 2026)Monthly payment of a US FHA mortgage with its mortgage insurance (MIP).
- VA loan calculator (US, 2026)Monthly payment of a US VA home loan for service members and veterans, with the funding fee.
- Home down payment calculatorYour down payment as an amount or a percentage, what you borrow and the cash you need.
- Credit card payoff calculatorHow many months to clear a credit card, and how much interest in total.
- Debt avalanche vs snowball calculatorCompare both methods to repay several debts with the same monthly budget.
- Debt repayment plan calculatorWith a monthly budget, when all your debts will be paid and how much interest it costs.
- Debt consolidation calculatorCompare your current debts with one new loan: monthly payment, length and total cost.
- Cash rebate vs low rate financingFor the same financed purchase, should you take the rebate or the low-rate loan?
- Debt-to-income ratio calculatorWhat share of your monthly income goes to repaying your debts.
- Mortgage overpayment calculatorHow much interest and how many months you save by paying more each month or a lump sum.
- Implied interest rate calculatorFind the hidden rate of a loan from the amount, the payment and the number of payments.
- Loan APR calculator with feesThe true rate of a loan when fees are paid upfront (US-style APR).
- Home equity loan calculatorHow much you can borrow against your home, and the monthly payment of that loan.
- HELOC payment calculatorPayments of a home equity line of credit: draw period, then repayment period.
- UK mortgage calculatorMonthly payment of a UK mortgage, repayment or interest-only.
- Canada mortgage calculatorCanadian mortgage payment by frequency: monthly, bi-weekly, accelerated or weekly.
- Detailed mortgage scheduleThe year-by-year table of a mortgage, with payoff date and an optional monthly overpayment.
- Investment interest calculatorHow much interest an investment earns, with or without regular deposits.
- Future value calculatorWhat an amount will grow to, with regular deposits, at a given rate.
- Growing savings plan calculatorA monthly saving that rises a little each year: final amount, also in today’s money.
- Time value of money calculator (PV, FV, rate, periods, payment)Find the unknown among present value, future value, payment, number of periods and rate.
- Annuity calculator (regular payments)Future value and present value of a series of equal payments over a fixed length.
- Regular withdrawals from savingsHow much to withdraw each month to use up savings in a given time, or how long they last.
- Term deposit and CD calculatorAmount at maturity and interest of a fixed-rate deposit locked for a set time.
- Bond price and yield calculatorYield to maturity from the price, or price from the yield, with duration.
- Present value calculator (discounting)What an amount, or a series of amounts, received later is worth today.
- Average return calculator (arithmetic and geometric)Simple and compound average of a series of returns, and their yearly version.
- IRR calculator (internal rate of return)The rate that brings the net present value of a series of cash flows to zero, with a warning when several rates fit.
- ROI calculator (return on investment)Gain as a percentage of the amount invested, and its yearly version if you give the length.
- Payback period calculatorHow many years the money coming in takes to repay the investment, with and without discounting.
- Home affordability calculatorThe indicative home price your income allows, with a debt ratio you choose.
- Rent affordability calculatorThe rent that matches the share of income you choose, and what you have left.
- College cost and savings calculatorThe total cost of studies with inflation, and how much to save each month until then.
- Pension vs lump sum calculatorMonthly pension or one lump sum: which is worth more for your time horizon.
- Social Security benefits calculator (US)A simplified estimate of your US Social Security retirement benefit by claiming age.
- Required minimum distribution (RMD) calculatorThe minimum you must withdraw each year from a traditional IRA or 401(k).
- Car lease calculator (US and French models)Your monthly car lease payment, US money-factor style or French LOA/LLD style.
- Depreciation calculator: straight-line, declining balance, SYDA year-by-year accounting depreciation schedule for an asset, with three methods.
- Sales commission calculatorCommission on sales, at one flat rate or with tiers.
- Rent vs buy calculatorCompare a renter’s and an owner’s wealth after several years, selling costs included.
- AdSense revenue estimatorProject display-ad revenue from pageviews, CTR, CPC and fill rate.
- RPM, CPM, CPC and CTR calculatorSee how CTR, CPC and fill rate combine into revenue per 1,000 pageviews.
- YouTube revenue estimatorEstimate revenue from monthly monetized views and your observed RPM.
- Affiliate profitability calculatorEstimate commissions, earnings per visitor and profit before tax.
- Freelance day-rate calculatorFind the revenue and day rate needed for a monthly take-home target, with verified profiles for France and the United States.
- ROAS and target CPA calculatorCalculate ROAS, acquisition cost, gross profit and paid-ad break-even.
Health
- BMI calculator (body mass index)An adult’s BMI from height and weight, with the WHO category.
- BMI weight range for a heightThe weights that match a BMI of 18.5 to 24.9 for an adult height.
- Basal metabolic rate (BMR) estimateThe energy the body uses at rest, estimated with two well-known formulas.
- Daily energy needs (estimate)A range of calories used in one day, from body size and activity.
- Macronutrient splitTurn a calorie intake into grams of carbs, protein and fat.
- Daily carbohydrate guideHow many grams of carbs a share of the day’s energy represents.
- Body fat estimate (US Navy method)An estimated body fat percentage from a tape measure: neck, waist and hips.
- Historical military body-fat formula estimatesCompare two older tape formulas (US Army 2023 and DoD 2002) that no longer reflect current official methods.
- One-rep max estimate (1RM)Estimate your one-repetition maximum from a lighter set.
- Heart rate zonesYour indicative training zones from your age and resting pulse.
- Protein intake guideA daily protein range based on your weight and activity.
- Fat intake guideTurn a share of fat (in % of energy) into grams per day.
- Total daily energy expenditureEstimate the calories you burn per day from your basal metabolic rate.
- Body surface areaEstimate body surface area in m² with the Mosteller and Du Bois formulas.
- Ovulation window estimateEstimate your ovulation date and most fertile days from your last period.
- Conception window estimateEstimate the likely conception period from the last period or the due date.
- Period calendar estimateEstimate the dates of your next periods, with an uncertainty margin.
- Weight references for a height, and their limitsCompare old “reference weight” formulas with the WHO BMI band, with no target to reach.
- Estimated lean body mass (Boer, James, Hume)Estimate an adult’s lean body mass with three named formulas, from height and weight.
- Energy used by an activity (MET)A range of calories burned during an activity, using the MET method.
- Pregnancy milestones: weeks, trimesters and key datesHow many weeks pregnant at a date, the trimester and key dates, from the last period or the due date.
- Estimated due date (Naegele’s rule)Estimate the due date from the last period, the conception date or a scan.
- Pregnancy weight gain references (IOM 2009)The weight gain references published by the Institute of Medicine by pre-pregnancy BMI.
- Estimate of the conception period of a pregnancyEstimate the likely conception period from the due date or a pregnancy dating.
- Running pace calculator (min/km and min/mile)Find the pace, time or distance of a run, in kilometres or miles.
- Estimated glomerular filtration rate (CKD-EPI 2021)Estimate the GFR from blood creatinine with the race-free CKD-EPI 2021 equation.
- Waist-to-height and waist-to-hip ratiosCalculate two descriptive body ratios from tape-measure readings.
- Indicative blood alcohol estimate (Widmark formula)An indicative range of blood alcohol content, which is never a permission to drive.
- Low BMI: understanding it and where to find helpRead a low BMI with care and find help resources, never with a weight to reach.
- Understanding BMI references and their limitsCalculate a BMI and read what the WHO references say, and do not say, depending on the situation.
- Transparent nutrition references per 100 gAn in-house, fully documented indicator comparing a food with European reference intakes.
Everyday
- Tip calculator and bill splitterThe tip, the total and how much each person pays.
- Download time calculatorHow long a file takes to download at your connection speed.
- Timesheet calculator with payTotal hours for the week, overtime and pay, from your start and end times.
- Concrete volume calculatorConcrete volume for a slab, footing, round columns or stairs, and how many bags.
- Fuel cost calculator for a tripHow many litres and how much money a car trip takes.
- Voltage drop calculator for a cableVoltage lost in a cable from its length, its cross-section and the current.
- Heating power estimateA rough order of magnitude of the heating power a home needs.
- Ohm’s law calculator: voltage, current, resistance, powerGive two values among V, I, R and P: we work out the other two.
- Room and floor area calculatorAdd up rectangles and take away openings to get a floor area.
- Compatibility game (just for fun)A little game: two nicknames give a fun percentage that means nothing.
- Engine power from torquePower in kW and horsepower from torque and engine speed.
- GDP calculator (expenditure approach)Gross domestic product from consumption, investment, government and foreign trade.
- GPA calculator (4.0 scale)Work out your GPA from letter grades (A, B+, C…) and the credits of each course, on the US 4.0 scale.
- Weighted grade average calculatorThe weighted average of your grades, and the grade you need on the next test to reach your goal.
- IP subnet calculator (IPv4 and IPv6)Network address, mask, usable address range and broadcast of an IPv4 subnet or an IPv6 prefix.
- Password generatorCreate a strong random password in your browser, with its strength in bits of entropy.
- Online dice rollerRoll 1 to 100 dice with 2 to 1000 faces (d6, d20…), with an optional bonus, and see each result.
- Stair calculator (Blondel rule)Number of steps, rise and going of each step, slope and comfort (2R + G) of a straight staircase.
- Resistor color code and series/parallel calculatorFind a resistor’s value from its color bands (4 or 5), or the equivalent resistance of several resistors.
- Appliance electricity cost calculatorWhat an electrical appliance costs to run: energy used in kWh and the price for the period, per day and per year.
- Mileage reimbursement calculator (your own rate)Add up your trips and multiply by your rate per kilometre to get the amount to claim.
- Golf handicap index calculator (WHS)Estimate your golf Handicap Index under the World Handicap System from your latest score cards.
- Sleep calculator (bedtime by sleep cycles)When to go to bed to wake up at the end of a 90-minute sleep cycle, or when to wake up.
- Molar concentration calculator (mol/L)The concentration of a solution in mol/L, from the dissolved mass or the amount of substance.
- Molar mass calculator for a chemical formulaThe molar mass in g/mol of a chemical formula, with the share of each element.
- Tire size comparison calculatorCompare two tire sizes: diameter, difference in %, and your true speed when the speedometer shows 100.
- Roof area calculatorThe real area of a roof from its footprint and pitch, with a margin and the number of tiles.
- Tile calculatorThe number of tiles and boxes for an area, joints and offcuts included.
- Mulch calculatorThe volume of mulch (bark, wood chips, straw) and the number of bags to cover a bed.
- Gravel calculatorThe volume and weight of gravel for a path or a yard, and the cost per tonne.
- Wind chill calculatorThe feels-like temperature in cold, windy weather, using the NWS and Environment Canada formula.
- Heat index calculatorThe feels-like temperature when it is hot and humid, using the US NWS method.
- Dew point calculatorThe temperature at which air becomes saturated and fog or dew appears.
Dates
- Exact age calculatorYour age in years, months and days, and how many days until your birthday.
- Days between two datesHow many days, weeks and weekdays lie between two dates.
- Date calculator: add or subtract daysAdd or subtract days, weeks, months or years to a date, or find the gap between two dates.
- Add and subtract hours and minutesAdd or subtract lengths of time in hours, minutes and seconds.
- Time between two timesThe time between a start and an end time, even past midnight, minus the break.
- Time zone converterWhat time is it elsewhere? Convert a date and time from one time zone to another.
- Time between two dates and timesThe exact time elapsed between two moments, including daylight saving changes.
- What day of the week? (date → day)Find the day of the week of any date, with its ISO week number and its day number in the year.
- Unix timestamp converterConvert a Unix timestamp to a readable date, or a date to a timestamp, in local time or UTC.
- Hijri date converterConvert a Gregorian date to a Hijri (Islamic) date or back, with the Umm al-Qura or tabular calendar.
- Countdown to a dateHow long until a date? Days, hours and minutes left before the event.
Conversions
- Unit converterLength, weight, volume and temperature: switch from one unit to another.
- Height: cm to feet and inches, and adult height estimateConvert a height between cm and feet-inches, or estimate a child’s adult height.
- Bra size calculator: EU, FR, UK and US sizesFind your bra size from two measurements, and the matching size in each country.
- Fuel economy converter: L/100 km, MPG and km/LConvert fuel economy between L/100 km, miles per gallon (US and UK) and km/L, or work it out after a trip.
- Power converter: kW, hp, PS, W, BTU/hConvert power between watts, kilowatts, metric horsepower (PS), mechanical horsepower (hp), BTU/h and kcal/h.
- Shoe size converter: EU, UK, US from foot lengthFind an indicative shoe size in Europe, the UK and the US from your foot length.
- Roman numerals converterTurn a number into Roman numerals (2026 → MMXXVI) or Roman numerals into a number, from 1 to 3,999.
- Base64 encoder and decoderEncode text to Base64 or decode Base64 back to text (UTF-8), with the URL-safe variant if needed.
- URL encoder and decoderEncode text for a URL (%20, %C3%A9…) or decode an encoded URL, as a single value or a full URL.
- Punycode converterEncode an international domain name to Punycode or decode it, on its own or inside a URL.
- Density calculatorThe density of an object or liquid from its mass and its volume.
- Mass from volume (weight of a liquid or material)How much a volume of water, oil, steel or concrete weighs.
- Weight force calculator (W = m × g)The weight of a mass in newtons, on Earth, the Moon, Mars or with your own gravity.
- Speed, distance and time calculatorType two of speed, distance and time: we work out the third.
- JSON parserCheck JSON syntax and see where parsing errors occur.
- JSON viewerShow JSON with readable indentation and count its top-level items.
- Base64 to image converterPreview and download an image from a Base64 string.
- XML formatterValidate and indent an XML document to make it easier to read.
- XML pretty printFormat XML with a choice of two-space or four-space indentation.
- XML editor and validatorCheck an XML document’s tags and structure as you enter it.
- JavaScript beautifierReindent JavaScript to make it easier to read and edit.
- Word counter and reading timeCount the words, characters, sentences and paragraphs of a text, with its reading time.
- Case and slug converterTurn text into uppercase, lowercase, camelCase, snake_case, kebab-case or a URL slug.
- UUID generatorGenerate random v4 UUIDs or time-ordered v7 UUIDs, up to 100 at a time.
- Regular expression testerTest a JavaScript regular expression on a text and see every match and its groups.
- SHA hash generatorCompute the SHA-256, SHA-384, SHA-512 or SHA-1 hash of a text, in hex or Base64.
- QR code generatorCreate a QR code for a link, text or Wi-Fi and download it as SVG.
- Color contrast checker (WCAG)Compute the contrast between a text color and a background color, and check AA and AAA levels.
- Cron expression explainerUnderstand a cron expression field by field and see its next run times.