Unit converters
Convert between metric, imperial and US customary units using exact, internationally defined conversion factors.
5 calculators
All unit converters
- Length ConverterConvert between metric, US and nautical length units, with the exact factor shown.
- Weight ConverterConvert kilograms, pounds, ounces, stone, tons and troy ounces, with the exact factor shown.
- Temperature ConverterConvert °C, °F, K and °R, with the formula worked through for your number.
- Volume ConverterConvert liters, gallons, pints, cups, fluid ounces and spoons, US and imperial, with the exact factor.
- Area ConverterConvert square feet, square meters, acres, hectares and square miles, with the exact factor.
Exact conversion factors
Since the 1959 international yard and pound agreement, imperial and US customary units are defined exactly in metric terms: one inch is exactly 2.54 cm and one pound is exactly 0.45359237 kg. The converters use these exact definitions, so results are as precise as the numbers you enter.
Watch for units that share a name but not a size. A US gallon (3.785 L) is smaller than an imperial gallon (4.546 L), and a US fluid ounce differs from an imperial one. The volume converter lists both.