How to convert units
- Choose a measurement type, such as Length or Temperature.
- Enter the value and choose the unit you are converting from and to.
- The result appears instantly. Click ⇄ to swap the units.
- Open “See this value in every unit” for a full conversion table.
Accurate conversions you can trust
The unit converter uses the exact international definitions: an inch is exactly 25.4 mm, a pound exactly 0.45359237 kg, and a US gallon exactly 3.785411784 litres. Temperature is converted through Kelvin, so Celsius, Fahrenheit, Kelvin and Rankine all agree, and values below absolute zero are rejected. Results are shown to up to ten significant figures.
Digital storage is a common source of confusion. Manufacturers use decimal units, where 1 GB is 1,000,000,000 bytes, while many operating systems use binary units, where 1 GiB is 1,073,741,824 bytes. That’s why a “1 TB” drive appears as about 931 GiB on your computer. This converter keeps both systems separate, and includes bits for internet speeds. US and UK (imperial) cups, pints and gallons are also listed separately because they are different sizes.
Categories and units
- Length: millimetres to miles and nautical miles.
- Weight: milligrams, grams, kilograms, tonnes, ounces, pounds, stones and tons.
- Area, volume and speed: metric and imperial units including hectares, acres, litres, gallons, km/h, mph and knots.
- Time and data: milliseconds to years, and bits to tebibytes.
Unit converter FAQ
Why is a month not exactly 30 days?
Months vary from 28 to 31 days, so the converter uses the average Gregorian month of 30.44 days and a year of 365.2425 days.
What’s the difference between MB and Mbit?
A megabyte (MB) is 8 megabits (Mbit). Internet speeds are usually given in megabits per second.
How do I convert cooking measurements?
Use the Volume category. Check whether your recipe uses US or UK units, as they differ.