Pounds to KG Converter
Convert pounds to kilograms — one pound is exactly 0.45359237 kg, so halve and take a little off. Results update as you type; exact factors shown.
One pound is 0.4536 kilograms — see the exact factor, not a rounded rule of thumb.
How the pounds to kg converter works
Mass converts through the kilogram. The avoirdupois pound has been exactly 0.45359237 kg since 1959, so an ounce is 28.349523125 g and a stone (14 lb) is 6.35029318 kg. A US short ton is 2,000 lb; an imperial long ton is 2,240 lb; a metric tonne is 1,000 kg.
The US uses customary units (US gallon, short ton, °F) in daily life; NIST SP 811 gives the exact SI factors.
Common mass conversions
| From | To | Units |
|---|---|---|
| 1 lb | 0.4536 kg | pound to kilograms |
| 5 lb | 2.268 kg | pounds to kilograms |
| 10 lb | 4.5359 kg | pounds to kilograms |
| 20 lb | 9.0718 kg | pounds to kilograms |
| 50 lb | 22.6796 kg | pounds to kilograms |
| 100 lb | 45.3592 kg | pounds to kilograms |
| 120 lb | 54.4311 kg | pounds to kilograms |
| 150 lb | 68.0389 kg | pounds to kilograms |
| 180 lb | 81.6466 kg | pounds to kilograms |
| 200 lb | 90.7185 kg | pounds to kilograms |
| 250 lb | 113.3981 kg | pounds to kilograms |
| 300 lb | 136.0777 kg | pounds to kilograms |
Units in this converter and their exact factors
| Unit | Symbol | One unit in kilograms |
|---|---|---|
| milligram | mg | 0.000001 kilogram |
| gram | g | 0.001 kilogram |
| kilogram | kg | 1 kilogram |
| tonne (metric ton) | t | 1,000 kilogram |
| ounce | oz | 0.0283495231 kilogram |
| pound | lb | 0.45359237 kilogram |
| stone | st | 6.35029318 kilogram |
| US ton (short) | US ton | 907.18474 kilogram |
| imperial ton (long) | long ton | 1,016.0469088 kilogram |
FAQFrequently asked questions about mass conversion
How many kg is 1 pound?
Exactly 0.45359237 kg.
What is 150 lb in kg?
68.04 kg.
What is the quick way to convert pounds to kg?
Halve it and take off ten per cent: 200 lb → 100 − 10 = 90 kg, and the exact answer is 90.7.
How many pounds in a stone?
Fourteen — so 154 lb is 11 stone.
Are US and UK pounds the same?
Yes for weight. The confusion is with tons: a US short ton is 2,000 lb, a UK long ton 2,240 lb.
Where these figures come from
- BIPM — The International System of Units (SI Brochure, 9th edition) — definitions of the base and derived units.
- NIST Special Publication 811 — Guide for the Use of the International System of Units — the exact conversion factors used here.
- National Institute of Standards and Technology (NIST) — United States's national measurement authority.
Last checked: September 2026. Conversion factors are fixed by definition and do not change with tax years or regulations.