Unit Converter
Utility ToolsConvert length, weight and temperature between units.
Runs entirely in your browser — nothing is uploaded
Features
- Length, weight, temperature and area, with nine length units alone.
- Metric, imperial and nautical units side by side.
- Swap the two units with one click.
- Temperature converted properly rather than by a ratio.
- Runs in your browser, so it works offline once the page has loaded.
How to use the Unit Converter
- 1Pick a category.
- 2Choose the two units and type a value.
- 3Read the converted figure, or swap the direction.
Frequently asked questions
Why is temperature handled differently from everything else?
Because temperature scales do not share a zero. Length and weight are ratio quantities — two metres is twice one metre — so converting is a single multiplication. Celsius, Fahrenheit and Kelvin each start their zero somewhere different, so converting needs an offset as well as a scale. Treating temperature as a ratio is why naive converters report 0°C as 0°F instead of 32°F.
Which units are covered?
Length from millimetres to nautical miles, including inches, feet, yards and miles. Weight from milligrams to tonnes, including ounces, pounds and stone. Temperature in Celsius, Fahrenheit and Kelvin. Area from square millimetres to square kilometres, including hectares, acres and square feet.
How accurate are the conversions?
Exact, where the definition is exact — an inch is defined as precisely 25.4 millimetres, a pound as 0.45359237 kilograms, and those are the factors used here. The only rounding is in how the result is displayed.
Is a US gallon the same as a UK one?
No, and it is the classic trap — a US gallon is about 3.79 litres and an imperial gallon about 4.55, a difference of roughly 20%. Where a unit differs between systems it is labelled, rather than left ambiguous.