Pound (lb)
Definition
The pound (symbol lb) is a unit of mass in both the imperial and US customary systems, equal to exactly 0.45359237 kilograms. The most common variant, the international avoirdupois pound, contains 16 ounces.
History
The pound descends from the Roman libra of about 328.9 grams, the source of its lb abbreviation. Medieval Europe used many local pounds; in England the avoirdupois pound, used for general weighing of goods, was fixed during the reign of Edward III at about 7,000 grains.
The 1959 international yard and pound agreement aligned U.S. and Commonwealth practice by defining the international pound as exactly 0.45359237 kilograms. The U.K. Weights and Measures Act of 1963 adopted the same value, and the pound remains in everyday use in the United States for personal weight, retail produce, and shipping.
Standard reference
Defined under the 1959 international yard and pound agreement as 0.45359237 kg exactly. Confirmed by NIST Special Publication 811.
Common conversions
| 1 lb | = 0.45359237 kg |
|---|---|
| = 453.59237 g | |
| = 16 oz | |
| = 0.0714286 st |