Unit Converter

Yes. The value box accepts whole numbers, decimals, plain fractions such as 7/8 and mixed numbers such as 3 1/2, and drops thousands separators, so 1,250 works too.

Both, labelled. US and UK gallons, pints and fluid ounces are separate units in the list because they differ by up to 20 percent, and metric tonnes, US short tons and UK long tons are listed by name rather than as one ambiguous "ton".

It is calculated from the same factor as your answer, at the sizes people usually look up — 1, 2, 5, 10, 20, 50, 100 and up. The factor line above it shows the multiplier in both directions so you can do the next one in your head, and for temperature it shows the written formula, such as °F = °C × 9/5 + 32.

Auto by default: up to 4 places for numbers of 100 or more, 6 between 1 and 100 and 8 below 1, with trailing zeros dropped. The Decimals box fixes it at 0 to 8 places instead, and the reference table follows the same setting. The Copy button copies the number as shown.

Conversions use the official defined factors, such as exactly 2.54 centimetres to an inch. Results show enough decimal places for everyday use and school work, so you can round them as the task needs.

A cup measures volume, not weight. A cup of flour weighs much less than a cup of sugar or honey, so the converter needs to know what you are measuring to give the right figure.

No. A US gallon is about 3.785 litres and a UK gallon about 4.546 litres. Check which one a recipe, car manual or fuel figure uses before converting.

Yes. It is built to work on small screens, with large boxes for typing numbers. The answer appears as soon as you enter a value, so it is quick to use in a shop or kitchen.

Neither. It is free, it opens straight away, and nothing you type is stored, so use it as often as a recipe or homework sheet needs.