Unit
Converter
Convert between any units of length, weight, temperature, volume, area, or speed — instantly, as you type.
Common Length Conversions
About this calculator
Each unit in a category is defined by a fixed ratio relative to a base unit — metres for length, kilograms for mass, and so on. Converting from unit A to unit B works by first converting A to the base unit, then dividing by B's ratio. This two-step approach means any pair of units in a category can be converted without needing a dedicated formula for each combination.
The SI (metric) system uses base-10 multiples, making conversions between metres, kilometres, and centimetres straightforward arithmetic. The Imperial system — still commonly used in the United States and partially in the UK — uses historical units with irregular conversion factors (12 inches to a foot, 3 feet to a yard, 1,760 yards to a mile), which is why a converter is particularly useful.