Convert any mass / weight unit
Pick any two units and convert between them: metric (milligrams to tonnes), avoirdupois (ounces, pounds, stones) and the two kinds of ton. The result updates as you type.
Every unit is defined against the kilogram. The pound is defined as exactly 0.45359237 kg, and the ounce, stone and both tons follow from it, so conversions between metric and imperial units are exact.
Units at a glance
| Unit | Symbol | Size |
|---|---|---|
| milligrams | mg | 1 milligram = 0.000001 kilograms |
| grams | g | 1 gram = 0.001 kilograms |
| kilograms | kg | The base unit for mass / weight. |
| metric tonnes | t | 1 metric tonne = 1,000 kilograms |
| ounces | oz | 1 ounce = 0.028349523125 kilograms |
| pounds | lb | 1 pound = 0.45359237 kilograms |
| stones | st | 1 stone = 6.35029318 kilograms |
| US tons | US ton | 1 US ton = 907.18474 kilograms |
| imperial tons | long ton | 1 imperial ton = 1,016.0469088 kilograms |
Three kinds of ton
A metric tonne is 1,000 kg. A US (short) ton is 2,000 pounds and an imperial (long) ton is 2,240 pounds. They differ by up to about 12%, so a bare "ton" needs checking; the table above shows each one in kilograms.
Mass and weight
Strictly, kilograms and pounds measure mass, and weight is the force of gravity on a mass. In everyday use on Earth people say "weight" for both, and the conversions here are exact for that purpose. For the force in newtons or pounds-force, use the force converter.
Stones
A stone is 14 pounds. It is used for body weight in the UK and Ireland, and is not used in the US.