How it is calculated
The value is converted to a base unit (metre, kilogram, litre…) and from there to every other unit using exact international factors, e.g.:
- 1 inch = 2.54 cm exactly, 1 foot = 30.48 cm, 1 mile = 1,609.344 m.
- 1 pound = 0.45359237 kg exactly, 1 ounce = 28.3495 g.
- 1 US gallon = 3.785 L; 1 UK gallon = 4.546 L.
Worked example
70 kg = 154.32 lb, 5.9 ft = 1.80 m and 100 °F = 37.78 °C.
Frequently asked questions
US vs UK gallon?
The US gallon is 3.785 L and the UK gallon 4.546 L — about 20% larger.
Why is 1 KB sometimes 1000 and sometimes 1024?
Decimal KB = 1000 bytes; binary KiB = 1024 bytes. Both are shown.
How many km in a mile?
1.609344 km.