Units
Mass converter
Convert grams, pounds, stone, and metric tonnes without mixing US and UK tons.
This tool processes files and text locally in your browser. Your content is not uploaded or stored by this site.
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What this tool does
The kilogram is the base. The pound is the international avoirdupois pound, exactly 0.45359237 kg. A short ton is 2000 lb; a long ton is 2240 lb. Carats are the metric jewellery carat of 200 mg.
How to use it
- Enter the mass.
- Pick source and destination units.
- Convert and copy the JSON.
Supported input
- A number and two mass units from the menu
Output
- JSON with the converted mass plus every other unit in the family
Privacy
This tool processes files and text locally in your browser. Your content is not uploaded or stored by this site.
ConvertPass does not include your input in analytics, URLs, or error reports. Encoding: Decimal numbers / SI kilogram. Limit: A single mass (4.0 KB).
Limitations
- Troy ounces used for precious metals are not in the menu. These ounces are avoirdupois.
- A ‘ton’ without US or UK in the name is not offered. Pick short ton or long ton, or use tonne for 1000 kg.
- Negative mass is refused.
Example
1 kilogram → pounds
{
"result": 2.20462262185,
"formatted": "1 kg = 2.20462262185 lb"
}
Troubleshooting
- The kitchen scale and this page disagree by a few grams
- Cheap scales round. This page uses the exact avoirdupois pound. It is not a legal-for-trade weighing instrument.
FAQ
Is a tonne the same as a ton?
No. A tonne is 1000 kg. A US short ton is 2000 lb. A UK long ton is 2240 lb.
Why is stone in the list?
Fourteen avoirdupois pounds. It is still used for body weight in some countries.
Can I convert slugs?
No. Engineering slugs are not in this public calculator.
Are carats jewellery carats?
Yes, 200 mg. They are not carats of gold purity.
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Last reviewed 16 August 2026. Report a problem. Reports do not include your input.