Unit Converters

Conversions between metric and imperial units, each with the exact factor, a worked example, and a reference table of the values people look up most.

Most of these factors are exact rather than approximate. An inch is defined as 2.54 centimeters, a pound as 0.45359237 kilograms, and a mile as 1,609.344 meters — all fixed by the international yard and pound agreement of 1959. Temperature is the exception, since Celsius and Fahrenheit have different zero points as well as different step sizes, which is why it needs an offset rather than a single multiplication.

Every converter works in both directions: enter a value on either side and the other updates.