Unit converter
Pick a category, enter a value and choose the units. The result updates as you type, and you can swap the two units in one click.
How to use it
- Choose a category such as length, weight or temperature.
- Type the value and select the unit you start from and the unit you want.
- Use the swap button to reverse the conversion.
Guide
Metric and imperial systems
Most of the world uses the metric system, based on metres, kilograms and litres. The United States mostly uses imperial units such as miles, pounds and gallons, and the United Kingdom mixes both. That is why conversions between kilometres and miles or kilograms and pounds come up so often when travelling, cooking or shopping online.
Handy conversions to remember
One kilometre is about 0.62 miles, one kilogram is about 2.2 pounds, and one litre is about 0.26 US gallons. One inch is exactly 2.54 centimetres and one foot is 0.3048 metres. For quick mental maths, multiply kilometres by 0.6 to estimate miles.
Why temperature is different
Length, weight and volume scale by a single factor, but temperature scales also have different zero points. Celsius and Fahrenheit differ in both zero and step size, and Kelvin starts at absolute zero. That is why temperature conversion needs a formula, not just a multiplication.
Frequently asked questions
How do I convert kilometres to miles?
Multiply kilometres by 0.621371 to get miles. For example, 10 km is about 6.21 miles. The converter does this for you and also works in reverse.
How do I convert Celsius to Fahrenheit?
Multiply the Celsius value by 9/5 and add 32. For example, 20 °C is 68 °F. To go back, subtract 32 and multiply by 5/9.
Are gallons and fluid ounces US or UK units?
This tool uses US gallons and US fluid ounces. The UK imperial gallon is larger, about 4.546 litres compared with 3.785 litres for the US gallon.