Unit Converter
Convert length, weight, temperature and volume between metric and imperial units — km to miles, kg to stones, Celsius to Fahrenheit, litres to UK gallons and more.
Unit converter
Metric ↔ imperial, four categories.
Volume uses the UK imperial gallon (4.546 L) and pint (568 ml), not US units.
Metric and imperial in the UK
Britain lives in two measurement worlds at once. We buy petrol in litres but quote fuel economy in miles per gallon; we weigh ourselves in stones and pounds but buy food in kilograms; road signs use miles while science uses metres. This converter bridges all four common categories — length, weight, temperature and volume — in either direction.
Handy conversions: 1 mile = 1.609 km, 1 stone = 6.35 kg, 0°C = 32°F, and 1 UK gallon = 4.546 litres. Type a value and pick your units to convert instantly.
Common conversion factors
| From | To | Multiply by |
|---|---|---|
| Kilometres | Miles | 0.621371 |
| Kilograms | Pounds | 2.204623 |
| Kilograms | Stones | 0.157473 |
| Litres | UK gallons | 0.219969 |
| Celsius → Fahrenheit | — | ×9/5 then +32 |
UK vs US gallons
A frequent source of confusion is the gallon: the UK imperial gallon is 4.546 litres, but the US gallon is only 3.785 litres. This converter uses UK units throughout, so a "gallon" here is the imperial one — the same figure our fuel cost calculator uses. For everyday percentage maths, see the percentage calculator.
Frequently asked questions
How do I convert kilometres to miles?
Multiply kilometres by 0.621371 to get miles, or divide miles by that figure to go the other way. For example, 10 km is about 6.21 miles. Select length in the converter and pick your units.
How do I convert kg to stones and pounds?
One kilogram is about 0.157 stone, and one stone is 6.35 kg. The weight mode converts between kilograms, grams, pounds and stones, which is handy for UK weights given in stones and pounds.
How do I convert Celsius to Fahrenheit?
Multiply the Celsius value by 9/5 and add 32. So 20°C is (20 × 9/5) + 32 = 68°F. The temperature mode also converts to and from Kelvin.
Is a UK gallon the same as a US gallon?
No. A UK imperial gallon is 4.546 litres, while a US gallon is 3.785 litres. This converter uses the UK imperial gallon and pint for volume, which is what's used in Britain.
Does the converter work both ways?
Yes. Choose the unit you have and the unit you want, and the converter works in either direction instantly as you type — metric to imperial or imperial to metric.