How to convert units
- Choose the quantity: length, weight, temperature, volume, area, speed, data size, time, pressure, energy, power, torque, fuel economy or angle.
- Type the value and pick the units to convert from and to. Use ⇄ to swap them.
- The answer updates as you type. Below it you see a quick reference table for that pair and the same value in every other unit.
Exact conversion factors
All factors are the exact international definitions: 1 inch is 2.54 cm, 1 foot is 0.3048 m, 1 mile is 1609.344 m, 1 pound is 0.45359237 kg and 1 US gallon is 3.785411784 litres. Temperatures are converted with formulas rather than a factor, because the scales have different zero points: °F = °C × 9/5 + 32. Results are shown to six significant figures, which is more precise than almost any real measurement.
Watch out for units with the same name. A US gallon (3.785 L) is smaller than a UK gallon (4.546 L), and so are US fluid ounces, pints and miles per gallon. In data sizes, a kilobyte here is 1000 bytes (the SI and storage-maker definition), while a kibibyte is 1024 bytes, which is what Windows reports as "KB". A food Calorie on a nutrition label is a kilocalorie.
The converter runs in your browser and remembers your last units on this device.
How many centimetres are in an inch?
Exactly 2.54 cm, by international agreement since 1959.
Why does my hard drive show less space than advertised?
Manufacturers use 1 GB = 1,000,000,000 bytes, but Windows divides by 1024³ and still calls it GB. A "1 TB" drive therefore shows about 931 GB. Convert TB to GiB to see the same number.
Is a stone the same as 14 pounds?
Yes. One stone is 14 lb, or 6.35029318 kg. It is still used for body weight in the UK and Ireland.
How do I convert L/100 km to mpg?
Divide 235.215 by the L/100 km figure to get US mpg (or 282.481 for UK mpg). The converter does this for you in Fuel economy.