1 Pound equals 0.453592 Kilograms.
| Pound (lb) | Kilogram (kg) |
|---|---|
| 0.001 lb | 0.000453592 kg |
| 0.01 lb | 0.00453592 kg |
| 0.1 lb | 0.0453592 kg |
| 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 |
| 500 lb | 226.796 kg |
| 1,000 lb | 453.592 kg |
To convert Pounds to Kilograms, multiply the value by 0.453592. This factor comes from the ratio of the two units' definitions: one Pound equals 0.453592 Kilograms.
For example: 1 Pound = 0.453592 Kilograms, and 10 Pounds = 4.53592 Kilograms.
To convert in the reverse direction — from Kilograms to Pounds — multiply by 2.20462.
The pound (lb) is the primary unit of mass in the US customary system and was historically the basis of both the avoirdupois and troy weight systems. The modern international pound is defined as exactly 0.45359237 kilograms. The abbreviation "lb" comes from the Latin "libra pondo" (a pound by weight), the same root that gives British currency its name — the pound sterling.
In the United States, pounds are used for body weight, food packaging (alongside ounces), livestock, and industrial loads. The pound is also the unit for measuring force in US engineering contexts: pounds-force (lbf) is a common unit in structural engineering, and engine output is sometimes given in horsepower alongside a torque figure in pound-feet (lb·ft). Body weight in the US is almost always communicated in pounds rather than kilograms.
One pound equals 16 avoirdupois ounces, 453.6 grams, or approximately 0.454 kg. A loaf of bread weighs about one pound; a gallon of water weighs about 8.34 pounds; and a typical bag of flour is sold in 5-pound increments. Globally, the pound still appears in British body-weight discussions, international boxing weight classes, and some agricultural contexts, though the metric system has otherwise displaced it throughout science and most commerce.
The kilogram is the SI base unit of mass — the unit from which all other mass units in the metric system derive. For most of its history (1889–2019), it was defined by a physical artifact: the International Prototype Kilogram (IPK), a cylinder of platinum-iridium alloy stored in a vault near Paris. In 2019, the definition was revolutionized: the kilogram is now defined by fixing the numerical value of the Planck constant to exactly 6.62607015 × 10⁻³⁴ J·s, making it the first base unit defined purely through a fundamental constant of nature.
In everyday life, the kilogram is the standard unit for body weight, food, and loads across most of the world. A liter of water has a mass of almost exactly one kilogram (0.9998 kg at room temperature). A typical adult human weighs 60–90 kg. A car weighs roughly 1,500 kg. The kilogram thus spans the range from a bag of flour to a small vehicle without requiring a change of units.
The change from artifact to fundamental-constant definition was scientifically momentous. For 130 years, the IPK was losing mass at a rate of about 50 micrograms per century relative to its official copies — a drift that was unmeasurable until metrology improved enough to notice it. The new definition eliminates this drift entirely: the kilogram is now as stable as the Planck constant itself, which is believed to be truly invariant across space and time.
1 Pound equals 0.453592 Kilograms.
To convert Pounds to Kilograms, multiply by 0.453592. For example, 1 Pound = 0.453592 Kilograms.
1 Kilogram equals 2.20462 Pounds.