Convert pounds to kilograms
1 lb = 0.453592 kg
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How many kilograms are in a pound?
One pound is 0.45359237 kilograms. To convert any amount, multiply by 0.45359237. Going the other way, one kilogram is 2.20462262 pounds.
What is the formula to convert lb to kg?
Multiply the pound figure by 0.45359237. So kg = lb × 0.45359237. For a quick mental estimate, dividing by about 2.2 gets you close enough for most everyday purposes.
What does a pound actually look like?
One pound is a block of butter, roughly. The international pound is exactly 0.45359237 kilograms. It is still the everyday body-weight and grocery unit in the United States.
And what is a kilogram?
One kilogram is a litre of water, near enough. The kilogram was redefined in 2019 in terms of the Planck constant, retiring the platinum-iridium cylinder in Paris that had defined it since 1889.
Is this conversion exact?
Yes. Since the 1959 international yard and pound agreement, the imperial and metric systems are related by exact definitions rather than measurements — the inch is exactly 25.4 mm and the pound exactly 0.45359237 kg. Everything derived from those, including this conversion, is therefore exact. Round at the end rather than partway through, since rounding lb before converting introduces an error the conversion then multiplies.
About lb to kg
How to convert pounds to kilograms
Multiply by 0.45359237. One pound is 0.45359237 kilograms, and one kilogram is 2.20462262 pounds.
kg = lb × 0.45359237
Worked example
10 lb = 4.535924 kg. For a sense of scale, one pound is a block of butter, roughly, and one kilogram is a litre of water, near enough.
About the pound
The international pound is exactly 0.45359237 kilograms. It is still the everyday body-weight and grocery unit in the United States.
About the kilogram
The kilogram was redefined in 2019 in terms of the Planck constant, retiring the platinum-iridium cylinder in Paris that had defined it since 1889.
Quick reference
| pounds | kilograms |
|---|---|
| 1 lb | 0.453592 kg |
| 2 lb | 0.907185 kg |
| 5 lb | 2.26796 kg |
| 10 lb | 4.53592 kg |
| 25 lb | 11.3398 kg |
| 50 lb | 22.6796 kg |
| 100 lb | 45.3592 kg |
| 1000 lb | 453.592 kg |
Getting it right
This conversion is exact by definition, so the only limit on accuracy is how many digits you keep. Round at the end rather than partway through — rounding lb to a whole number before converting introduces an error that the conversion then multiplies.
Other weight & mass conversions
Convert kilograms back to pounds, or pick any other pair with the full unit converter. Related: lb to g, lb to oz, lb to t.