Convert Pounds to Kilograms
Convert Pounds to Kilograms instantly. 1 Pound (lb) equals 0.4536 Kilograms (kg).
Pounds to Kilograms conversion table
| Pounds (lb) | Kilograms (kg) |
|---|---|
| 1 lb | 0.4536 kg |
| 2 lb | 0.9072 kg |
| 3 lb | 1.3608 kg |
| 5 lb | 2.268 kg |
| 10 lb | 4.5359 kg |
| 20 lb | 9.0718 kg |
| 50 lb | 22.6796 kg |
| 100 lb | 45.3592 kg |
| 500 lb | 226.7962 kg |
| 1,000 lb | 453.5924 kg |
1 Pound = 0.4536 Kilograms · multiply Pounds by 0.4536
About converting Pounds to Kilograms
Pounds (lb) and Kilograms (kg) are both units of weight & mass, so converting between them is a single multiplication: multiply your Pounds figure by 0.4536. Ten Pounds comes to 4.5359 Kilograms, and a hundred works out at 45.3592 Kilograms.
Rule of thumb: going from Pounds to Kilograms divides, so the figure always shrinks — it takes about 2.2046 Pounds to make a single Kilogram. If your answer came out bigger, you have the conversion the wrong way round.
What is a Pound?
The pound descends from the Roman libra pondo, "a pound by weight", which is why English took pound from the second word and the abbreviation lb from the first. The version used here is the avoirdupois pound, from an Old French phrase meaning "goods of weight" — the merchants’ system for ordinary bulk trade. A separate troy pound survived for precious metals and was never the same size. The 1959 international yard and pound agreement finally fixed the avoirdupois pound at exactly 0.45359237 kilograms across the English-speaking world, ending a long tail of national variants.
What is a Kilogram?
The kilogram was the last SI unit still defined by a physical object — the International Prototype Kilogram, a platinum-iridium cylinder kept in a vault near Paris since 1889. The problem was that it drifted. Careful comparisons against its official copies showed the masses diverging by tens of micrograms, and because the prototype simply was the kilogram by definition, there was no way to say which side had changed. In 2019 it was redefined in terms of the Planck constant, so any properly equipped lab can now realise a kilogram from physics rather than from an artefact.
To put both in perspective: a pound is roughly a loaf of bread, while a liter of water weighs about a kilogram.
The converter above updates as you type, and the table lists common values for quick reference. Need the opposite direction? Use the Kilograms to Pounds converter, or browse all Weight & Mass converters.
Frequently asked questions
How many Kilograms are in one Pound?
There are 0.4536 Kilograms in one Pound.
How do I convert Pounds to Kilograms?
Multiply the number of Pounds by 0.4536. For example, 10 Pounds = 4.5359 Kilograms.
What is 100 Pounds in Kilograms?
100 Pounds is equal to 45.3592 Kilograms.
How do I convert Kilograms to Pounds?
Multiply the Kilograms value by 2.2046 (or divide by 0.4536).
Is this Pounds to Kilograms conversion exact?
The definition is exact — Pounds and Kilograms are both fixed against the same base by international agreement — but the decimal shown here is rounded for readability, because the true ratio does not terminate. For engineering or scientific work, carry more decimal places than this page displays.
What is a Pound?
The pound descends from the Roman libra pondo, "a pound by weight", which is why English took pound from the second word and the abbreviation lb from the first. The version used here is the avoirdupois pound, from an Old French phrase meaning "goods of weight" — the merchants’ system for ordinary bulk trade. A separate troy pound survived for precious metals and was never the same size. The 1959 international yard and pound agreement finally fixed the avoirdupois pound at exactly 0.45359237 kilograms across the English-speaking world, ending a long tail of national variants.
What is a Kilogram?
The kilogram was the last SI unit still defined by a physical object — the International Prototype Kilogram, a platinum-iridium cylinder kept in a vault near Paris since 1889. The problem was that it drifted. Careful comparisons against its official copies showed the masses diverging by tens of micrograms, and because the prototype simply was the kilogram by definition, there was no way to say which side had changed. In 2019 it was redefined in terms of the Planck constant, so any properly equipped lab can now realise a kilogram from physics rather than from an artefact.