Every calculator you need, in one place.
Free calculators for money, health, maths, business and daily life — with the rules of your own country built in.
Popular calculators
- Science & engineeringScientific calculatorA full scientific calculator: trigonometry, logarithms, powers, roots, factorials and constants, in degrees or radians.
- HealthBMI calculatorCalculate body mass index in metric or imperial units, with the WHO category and the matching weight range.
- MathsPercentage calculatorFive percentage calculations in one tool: percent of a number, share, change between two values, discount and increase.
- BorrowingMortgage calculatorWork out the monthly payment, the total interest and the outstanding balance of a fixed-rate mortgage or loan.
- Women's healthOvulation calculatorEstimate your ovulation date, fertile window, next periods and expected due date from your cycle length.
- DatesAge calculatorWork out an exact age or the duration between two dates, in years, months, weeks and days.
- BusinessVAT calculatorAdd or remove VAT, GST or sales tax at your country's standard rate, with the net, tax and gross amounts.
- ConversionUnit converterConvert mass, length, volume, area, temperature, speed, pressure and data between metric and imperial units.
- Women's healthPregnancy due date calculatorEstimate your due date from your last period or conception date, with gestational age, trimester and key milestones.
- Saving & investingCompound interest calculatorSee what savings grow to with regular contributions, compounding, and the tax your country applies to the gains.
- EverydayTip calculatorSplit a bill, add a tip at any percentage, and round the total so the table pays a clean number.
- CarFuel cost calculatorWork out what a journey costs in fuel, in litres per 100 km, miles per gallon or kilometres per litre.
Categories
- Saving & investingCompound interest, savings goals, returns, inflation and retirement.7
- BorrowingMortgages, credit cards and what a lender will let you borrow.5
- BusinessPricing, margin, tax and the point where a product pays for itself.7
- HealthBody measurements and cycle dates, with clear limits on what they mean.8
- Women's healthCycle, fertility and pregnancy dates, with their limits clearly stated.4
- MathsPercentages, statistics and number theory, with the working shown.9
- Science & engineeringA scientific calculator, electricity, density, motion and screens.5
- DatesAges, durations and working days between two dates.5
- ConversionUnits, number bases, file sizes, aspect ratios and kitchen measures.5
- Home & DIYPaint, tiles, concrete and what your appliances cost to run.4
- CarFuel, charging an electric car, and what a car loses in value.3
- EverydayTips, sleep and grades — the small sums that come up constantly.3
Why use Calcolia
- Free, no sign-upEvery calculator works straight away. No account, no paywall, no trial.
- Runs in your browserYour figures stay on your device. Nothing you type is sent to a server.
- Built for your countryPension ages, VAT rates and tax on savings follow the country you pick.
- Shows the formulaEach page gives the maths it used, with a worked example you can check.
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