Unit Converter

How it works

1. 1Pick a category — length, mass, volume, area, speed or temperature.
2. 2Choose the unit you have and the unit you want; type a value into either side.
3. 3The swap button flips the two units without re-typing the value.

Common questions

Why is temperature handled differently from the others?

Length, mass, volume, area and speed all convert by multiplying by a fixed factor — 1 mile is always 1.609344 km. Temperature scales have different zero points, so converting needs a formula (subtract, then multiply) rather than a single factor. The tool applies the right one automatically.

Which gallon, pint and fluid ounce — US or UK?

Both are offered as separate units, labelled US or UK, because they are genuinely different sizes: a UK gallon is about 20% larger than a US gallon.

How many decimal places does the answer use?

Up to six significant decimal places, trimmed of trailing zeros. A conversion between very different unit sizes (millimetres to miles, for instance) can still show a long decimal — that is the actual value, not a display error.