Unit Converter

It converts between units of length, mass and volume in one tool. Because these are different physical quantities, the converter only converts within a quantity — it will not convert a length into a mass.

This tool supports 18 units: 8 of length, 4 of mass and 6 of volume (US customary for liquid measure). For temperature, area, speed, pressure, energy, power, data size or time, use the dedicated converter for that quantity — each covers far more units than fit in one universal tool.

Only within the same physical quantity — length to length, mass to mass, volume to volume. Asking for metres to kilograms returns an explanation rather than a number, because no conversion factor exists between different quantities. Converting a volume to a mass additionally requires a density, which this tool does not ask for.

Every factor here is exact by definition, not an approximation: 1 in = 2.54 cm, 1 lb = 0.45359237 kg and 1 US gallon = 231 in³ are definitions, so the only rounding is the final display rounding you choose (up to 15 decimal places).

US customary. The US gallon, quart, cup and fluid ounce used here are all liquid-measure units defined from the 231 in³ US gallon. The UK Imperial gallon is about 20% larger, so if you need Imperial volumes, check the units carefully — this tool does not include them.