Weight & Mass Converter
Convert a weight (mass) into every metric, US customary and carat unit at once.
Weight units and definitions
The size of each unit is listed below. The pound and ounce are the avoirdupois units used in everyday weighing, not the troy ounce used for precious metals.
| Unit | Size of one unit | Definition and source |
|---|---|---|
| Metric (SI) | ||
| t (metric ton, tonne) | 1,000 kg | Not the U.S. short ton or the UK long ton: those are different units and are not included |
| kg (kilogram) | 1 kg | Metric (SI) unit |
| g (gram) | 0.001 kg | Metric (SI) unit |
| mg (milligram) | 0.000001 kg | Metric (SI) unit |
| US customary (avoirdupois) and carat | ||
| pound (lb) | 0.45359237 kg | 0.45359237 kg (the value used by this tool) |
| ounce (oz) | 0.028349523125 kg | 1/16 of a pound (avoirdupois ounce, not the troy ounce) |
| carat (ct) | 0.0002 kg | Exactly 200 mg (the metric carat). NIST SP 811 |
The calculator converts your value to kilograms, then divides by the size of each unit. Calculations use exact fractions, and the only rounding is the one applied when a value is displayed.
Examples
- 1 pound = 0.45359237 kg = 453.59237 g = 16 ounces
- 1 ounce = 28.349523125 g
- 1 kg ≈ 2.204623 lb
- 1 carat = 200 mg
- 1 tonne = 1,000 kg
Notes
- Weight and mass are different quantities (a kilogram-force is a unit of force, not mass), but everyday scales show mass in kilograms or pounds, and this converter treats them as mass.
- "Ton" has several meanings. This converter uses the metric ton (tonne, 1,000 kg). The U.S. short ton and the UK long ton are different units and are not included.
- You can enter decimals (up to 12 digits before the decimal point and 6 decimal places). Use a period as the decimal separator.
Sources
The definitions on this page come from the sources below. Some values are the exact values this tool uses (for example, the pound as exactly 0.45359237 kg), and the sources may list them rounded; the notes in the table say which values are used by this tool.
Frequently asked questions
How many grams are in a pound?
1 pound is 453.59237 grams.
How many ounces are in a pound?
16 ounces (avoirdupois) make 1 pound.
How do I convert kilograms to pounds?
Divide the kilograms by 0.45359237, or multiply by about 2.204623. In this tool, just pick the units.