Converters
Convert between metric and imperial units without guessing which factor to apply. Each converter normalises your input to a base unit and then converts to the target unit, so every pairing uses the same underlying definitions.
The conversion factors used here are the internationally agreed definitions — one inch is exactly 25.4 millimetres, one pound is exactly 0.45359237 kilograms. Where a factor is exact by definition rather than approximate, the page says so.
All converters
- Length ConverterConvert between metric and imperial lengths with exact factors.
- Weight ConverterConvert between kilograms, pounds, stone, ounces and tonnes.
- Temperature ConverterConvert between Celsius, Fahrenheit, Kelvin and Rankine.
- Area ConverterConvert between square metres, square feet, acres and hectares.
- Volume ConverterConvert litres, gallons, pints and cups — US and imperial kept separate.
- Speed ConverterConvert between km/h, mph, metres per second and knots.
- Time ConverterConvert between seconds, minutes, hours, days, weeks and years.
- Data Storage ConverterConvert data sizes, with decimal (KB) and binary (KiB) kept separate.
- Pressure ConverterConvert between bar, psi, pascals, atmospheres and mmHg.
- Energy ConverterConvert joules, calories, kilowatt hours and BTU.
- Power ConverterConvert watts, kilowatts, horsepower and BTU per hour.
- Frequency ConverterConvert between hertz, kHz, MHz, GHz and revolutions per minute.
- KG to LBS ConverterConvert kilograms to pounds with a quick reference table.
- LBS to KG ConverterConvert pounds to kilograms with a quick reference table.
- KM to Miles ConverterConvert kilometres to miles, including race distances.
- Miles to KM ConverterConvert miles to kilometres, including race distances.
- CM to Inches ConverterConvert centimetres to inches, with height references.
- Inches to CM ConverterConvert inches to centimetres with a reference table.
- Celsius to Fahrenheit ConverterConvert °C to °F, with weather and cooking references.
- Fahrenheit to Celsius ConverterConvert °F to °C, with weather and oven references.