Unit Converter
Convert between different units instantly
About Unit Converter
Converts between units of length, weight, temperature, area and volume. Pick a category, choose the two units, and enter a value in either field.
Why temperature is different
Length, weight, area and volume conversions are pure multiplication — a metre is always 3.28084 feet, whatever the value. Temperature is not, because the scales have different zero points. Celsius to Fahrenheit needs °F = °C × 9/5 + 32, an offset as well as a scale, which is why 0 °C is 32 °F rather than 0.
Why do US and UK measures with the same name differ?
Because they descend from separate standardisations. A US fluid ounce is about 4% larger than an imperial one, while a US gallon is about 17% smaller than an imperial gallon. Recipes and fuel economy figures are the usual places this bites — always check which system a source is using.
How precise are the results?
Some conversions are exact by definition — the inch, the pound and the mile are defined in metric terms. Others are irrational or rounded, so results are shown to a practical number of decimals. For engineering or laboratory work, use the full defined constant rather than a rounded display value.