To convert kilograms to pounds (kg to lb), multiply by 2.2046226. 1 kilogram equals 2.2046226 lb, about 2.2 times as much as a loaf of sandwich bread.
| kilograms | pounds |
|---|---|
| 1 kilogram | 2.2046226 lb |
| 2 kilograms | 4.4092452 lb |
| 5 kilograms | 11.023113 lb |
| 10 kilograms | 22.046226 lb |
| 25 kilograms | 55.115566 lb |
| 50 kilograms | 110.23113 lb |
| 100 kilograms | 220.46226 lb |
| 250 kilograms | 551.15566 lb |
| 500 kilograms | 1,102.3113 lb |
| 1000 kilograms | 2,204.6226 lb |
Definition: The SI base unit of mass - 1,000 grams.
History: For 130 years, the kilogram was defined by a single physical object: a golf-ball-sized cylinder of platinum and iridium nicknamed "Le Grand K," locked in a vault outside Paris and taken out for cleaning only once every 40 years. Every kilogram on Earth was, technically, defined by how much that one specific object weighed - which became a real problem once scientists discovered it had lost about 50 micrograms of mass over its lifetime, for reasons nobody could fully explain. In 2019, the kilogram was redefined using Planck's constant instead, a fundamental property of physics that can't drift, get scratched, or need cleaning.
Current use: The standard unit of mass in nearly every country on Earth, used in science, medicine, and everyday commerce.
Definition: Exactly 0.45359237 kilograms - 16 ounces.
History: The pound descends from the Roman "libra," which is also where the abbreviation "lb" comes from - it never matched the English word at all. It went through numerous competing regional definitions over the centuries until the "avoirdupois" pound was standardized, then finally locked to an exact metric value in 1959 by international agreement - meaning the pound has been officially defined in terms of the kilogram, not the other way around, for over 60 years.
Current use: Everyday weight in the US, including body weight, food packaging, and shipping. The UK largely moved to metric but still uses pounds, and stone, for body weight specifically.
Because a pound is exactly 0.45359237 kilograms by definition, this factor is exact rather than measured.
For a quick estimate, multiply by 2.2. That is off by about 0.2%, which is fine for a rough figure and not fine for anything you are paying for or building to. Use the exact factor of 2.20462 when it matters.
The reverse factor is 0.454, so one pound is that many kilograms. Two decimal places is plenty for most purposes, and three is more than a tape measure can justify.
To anchor the scale: 1 kilogram is about 2.2 lb.