Weight Converter
Convert mass across nine units, including the three different tons that cause the most confusion.
All units
How to use the Weight Converter
- Enter the weight you want to convert.
- Choose the source and target units.
- Read the result, or scan the table for every unit at once.
The three tons
"Ton" means three different things, differing by up to 10%:
| Name | Equals | Used in |
|---|---|---|
| Metric tonne | 1,000 kg (2,204.6 lb) | Most of the world, international trade |
| US short ton | 2,000 lb (907.18 kg) | United States |
| UK long ton | 2,240 lb (1,016.05 kg) | Historic British use, shipping |
Shipping documents and freight quotes are where this matters most. If a figure is unlabelled, the metric tonne is the safest assumption outside the United States.
Mass versus weight
Strictly, mass is the amount of matter in an object and weight is the force gravity exerts on it. Mass is measured in kilograms; weight is properly measured in newtons. On the Moon your mass is unchanged but your weight is about one sixth.
Everyday language ignores this, and so does this converter — like every scale you have used, it treats kilograms and pounds as interchangeable measures of the same thing. That is correct anywhere on Earth's surface, where gravity varies by only a fraction of a percent.
Frequently asked questions
How many pounds in a kilogram?
Exactly 1 kg = 2.2046226218 lb, since the pound is defined as exactly 0.45359237 kg. The familiar 2.2 is accurate enough for most purposes.
What is a stone?
14 pounds, or about 6.35 kg. It is still used for body weight in the UK and Ireland, where a weight is usually spoken as "11 stone 4" rather than in pounds alone.
Why is an ounce of gold different?
Precious metals use the troy ounce, about 31.10 g, rather than the avoirdupois ounce of 28.35 g used for everything else. This converter uses the ordinary ounce.
Are US and UK pounds the same?
Yes. Both use the international avoirdupois pound of exactly 0.45359237 kg, agreed in 1959.
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