Pounds to Kilograms; Kilograms to Pounds Converter

lb to kg / kg to lb

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Weight Unit Description


The pound or pound-mass is a unit of mass used in British imperial and United States customary systems of measurement. Various definitions have been used; the most common today is the international avoirdupois pound, which is legally defined as exactly 0.45359237 kilograms, and which is divided into 16 avoirdupois ounces. The international standard symbol for the avoirdupois pound is lb; an alternative symbol is lbm (for most pound definitions), # (chiefly in the U.S.), and or ″̶ (specifically for the apothecaries' pound).

The unit is descended from the Roman libra (hence the abbreviation "lb"). The English word pound is cognate with, among others, German Pfund, Dutch pond, and Swedish pund. These units are historic and are no longer used formally (replaced by the metric system), though informal use of the term to mean 500 grams is still heard across Europe and beyond.


The kilogram (also kilogramme) is the base unit of mass in the International System of Units (SI), the metric system, having the unit symbol kg. It is a widely used measure in science, engineering and commerce worldwide, and is often simply called a kilo colloquially.

The kilogram was originally defined in 1795 as the mass of one litre of water. Modern superseding definitions of a kilogram agree with this original definition to within 30 parts per million. In 1799, the platinum Kilogramme des Archives replaced it as the standard of mass. In 1889, a cylinder of platinum-iridium, the International Prototype of the Kilogram (IPK) became the standard of the unit of mass for the metric system and remained so until 2019. The kilogram was the last of the SI units to be defined by a physical artefact. (source: wikipedia)

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