191+ free tools
Free Online Calculators for Everyday Life
Calculate anything, instantly: from health and money to cars, tech and unit conversions. Every tool shows the formula, a worked example and its sources, so you can trust the number.
191Calculators
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14 toolsHealth & FitnessBody measurements, pregnancy dates, hydration and heart-rate training zones.
12 toolsMoney & FinanceLoans, savings, budgets and everyday money maths.
8 toolsCars & MotorcyclesFuel, engine and gearing calculators for riders, drivers and home mechanics.
5 toolsTech & ITUptime, storage, cloud and project numbers for people who build software.
4 toolsDate & CalendarDate differences, calendars and time conversions.
8 toolsMaths & StudyPercentages, fractions, ratios, averages, grades and everyday school and work maths.
140 toolsUnit ConvertersLength, weight, volume, pressure, power and more.Start hereOur most useful calculators
- 1BMI CalculatorBody mass index with WHO categories and a healthy weight range for your height.
- 2Mortgage CalculatorMonthly mortgage payment with down payment, property tax and insurance, plus total interest.
- 3Calorie Calculator (TDEE)Daily calories to maintain, lose or gain weight, using the Mifflin-St Jeor equation.
- 4Loan CalculatorMonthly payment, total interest and an amortisation schedule for any fixed-rate loan.
- 5Pregnancy Due Date CalculatorEstimated due date, how many weeks pregnant you are and key milestones.
- 6Compound Interest CalculatorFuture value of savings with monthly, yearly or daily compounding and regular deposits.
Popular convertersQuick everyday conversions
- 1Centimetres to Inches ConverterConvert centimetres (cm) to inches (in) instantly, with a table of everyday values.
- 2Kilograms to Pounds ConverterConvert kilograms (kg) to pounds (lb) instantly, with a table of everyday values.
- 3Degrees Celsius to Degrees Fahrenheit ConverterConvert degrees Celsius (°C) to degrees Fahrenheit (°F) instantly, with a table of everyday values.
- 4Megabits per Second to Megabytes per Second ConverterConvert megabits per second (Mbps) to megabytes per second (MB/s) instantly, with a table of everyday values.
- 5Terabytes to Tebibytes ConverterConvert terabytes (TB) to tebibytes (TiB) instantly, with a table of everyday values.
- 6BTU per Hour to Watts ConverterConvert BTU per hour (BTU/h) to watts (W) instantly, with a table of everyday values.
Guide · 3 min readBMI vs Waist Size: Which Tells You More About Your Health?What BMI and waist circumference each measure, their official cut-offs, where BMI misleads, and how to use both together for a better picture of weight-related health risk.Guide · 2 min readCelsius and Fahrenheit: Quick Conversions for Cooking, Weather and FeverThe exact Celsius–Fahrenheit formulas, a mental shortcut, and ready-made tables for oven temperatures, weather and body temperature, with tips to avoid common mistakes.Guide · 3 min readHow Much House Can You Afford? The 28/36 Rule ExplainedUse the 28/36 rule to estimate an affordable mortgage payment from your income, turn that payment into a loan amount, and see what changes it: rates, debts, down payment and costs.
Built for accuracy, designed for simplicity
Most calculators give you a number and nothing else. Ours show the formula, a worked example with real figures and the sources the method comes from, such as the WHO for health measurements or NIST for unit definitions. Everything runs in your browser: no sign-up, and the numbers you type are not sent anywhere.