Pounds to kilograms
Multiply pounds by 0.453592 to get kilograms.
10 lb = 4.5359 kg
How to convert pounds to kilograms
The kilogram is the SI base unit of mass, fixed since 2019 by defining the Planck constant as exactly 6.62607015×10⁻³⁴ J·s. The pound is exactly 0.45359237 kilograms — the international avoirdupois pound fixed by the 1959 agreement of the US, UK and Commonwealth.
Worked example — 10 lb: 10 × 0.453592 = 4.5359 kg.
Pounds to kilograms table
| Pounds | Kilograms |
|---|---|
| 0.5 lb | 0.226796 kg |
| 1 lb | 0.453592 kg |
| 2 lb | 0.907185 kg |
| 5 lb | 2.268 kg |
| 10 lb | 4.5359 kg |
| 25 lb | 11.3398 kg |
| 50 lb | 22.6796 kg |
| 75 lb | 34.0194 kg |
| 100 lb | 45.3592 kg |
Reverse and related
About pounds and kilograms
Pound (lb)
1 lb = 0.453592 kgDefinition. Exactly 0.45359237 kilograms — the international avoirdupois pound fixed by the 1959 agreement of the US, UK and Commonwealth
History and origin
The pound descends from the Roman libra, whose name still gives the symbol lb. Many regional pounds circulated for centuries before the 16-ounce avoirdupois pound became the English-speaking standard for trade. In 1959 the United States, the United Kingdom and other Commonwealth countries signed the international yard and pound agreement, fixing the pound at exactly 0.45359237 kilograms.
Current use
The pound is the everyday unit of weight in the United States, and informally in the United Kingdom, for body weight, food packaging and shipping, while most of the world states the same weights in kilograms.
Source: NIST Handbook 44, Appendix C §5 (Tables of Equivalents)
Kilogram (kg)
1 kg = 2.2046 lbDefinition. The SI base unit of mass, fixed since 2019 by defining the Planck constant as exactly 6.62607015×10⁻³⁴ J·s
History and origin
The kilogram began in 1795 as the mass of one litre of water at the melting point of ice, and from 1889 was embodied in a platinum-iridium cylinder kept near Paris, the International Prototype Kilogram. In 2019 the SI retired that physical artefact and redefined the unit through a fixed value of the Planck constant, leaving its size unchanged.
Current use
It is the base unit of mass almost everywhere on Earth. The main everyday exception is the United States, where people weigh in pounds even though US science, medicine and industry work in kilograms.
Source: BIPM, The International System of Units (SI), 9th ed. (2019)
Where people use this
Pounds: body weight in the US, gym plates, shipping weights. Kilograms: body weight outside the US, groceries and produce, checked-luggage limits. A 150 lb adult is about 68 kg, and a 50 lb bag is 22.7 kg.
Every value is carried to full double precision; the display is rounded.
Sources: BIPM, The International System of Units (SI), 9th ed. (2019); NIST Handbook 44, Appendix C §5 (Tables of Equivalents).
Questions people ask
How many kg is 1 pound?
One pound is 0.4536 kilograms. To convert, multiply the pounds by 0.4536, so 10 lb is about 4.54 kg.
How many kg is 150 pounds?
150 pounds is about 68 kg (150 × 0.453592 = 68.04 kg), a common bodyweight conversion.
How do you convert lbs to kg?
Multiply the pounds by 0.4536, or divide by 2.2046. For a rough estimate, halve the pounds and take off about 10% — 150 lb becomes 75 − 7 = 68 kg.
Is a pound half a kilogram?
Close but not exact: one pound is 0.4536 kg, a little under half a kilogram, so two pounds is a touch less than 1 kg.
What is 200 lbs in kg?
200 pounds is about 90.7 kg (200 × 0.453592). A 50 lb bag is 22.7 kg.