Pound (mass)

A pound (usually abbreviated as lb, plural lbs) is a unit used to measure the mass of something. It is used in the imperial system and the United States customary system. It is related to the Pound (force). There are a number of different definitions. The most commonly used definition today is the international avoirdupois pound. This is equal to 0.45359237 kilograms, and is divided into 16 avoirdupois ounces.^[1]

The abbreviation lb is for the Latin word libra, meaning weight.

Avoirdupois pound

The avoirdupois pound (abbreviation lb., plural lbs.) is the most common unit. This type is used for all purposes except the uses of the troy pound. Most people from the United States, United Kingdom, Ireland, Canada, Liberia and Burma use this as their standard measure of their personal mass.

Units	Grains	Drachms	Ounces	Pounds	Stones	Quarters	Short Hundredweights (Centals)	Long Hundredweights	Short Tons	Long Tons	Metric Value
Avoirdupois pound	7,000	256	16	1	​1⁄14	​1⁄28	​1⁄100	​1⁄112	​1⁄2,000	​1⁄2,240	453.59237 Grammes

Troy pound

The troy pound (abbreviation t lb., plural t lbs.) is generally not used anymore. It was used in England by apothecaries and jewellers. A troy pound contains 12 troy ounces. The troy ounce is still used to measure the mass of precious metals and gems.

Units	Grains	Pennyweights	Ounces	Pounds	Metric Values
Troy Pound	5,760	240	12	1	373.2417216 Grammes

Metric pound

In some European countries, a metric pound is an informal term for half a kilogram (500 grams). In the Netherlands, however, the metric pound (Dutch: pond) used to be equal to 480 grams, but nowadays a Dutch pound equals 500 grams. A Dutch 'ons' (ounce) is equal to 100 grams, and it is often said that 5 ons is 1 pond.

Comparison

Units	Avoirdupois pounds	Troy pounds	Metric value
Avoirdupois pound	1	1​155⁄875	453.59237 Grammes
Troy pound	​720⁄875	1	373.2417216 Grammes