Pound to Kilogram Converter

A pound (lb) is a unit of mass in the imperial and US customary systems, equal to 16 ounces or approximately 453.592 grams. The avoirdupois pound is the most commonly used variant.

The pound has ancient origins, derived from the Roman 'libra pondo' meaning 'pound weight'. Various pound definitions existed throughout history until the avoirdupois pound was standardized. The international avoirdupois pound was defined as exactly 453.59237 grams in 1959.

Pounds are primarily used in the United States, United Kingdom, and a few other countries for measuring body weight, food products, and everyday objects. They're standard for personal scales, grocery items, shipping weights, and in fitness and health contexts in these regions.

A kilogram (kg) is the base unit of mass in the International System of Units (SI), equal to 1,000 grams. It is defined by the Planck constant and represents the mass of the International Prototype of the Kilogram.

The kilogram was originally defined in 1795 as the mass of one liter of water at 4°C. It was later redefined using a physical prototype - a platinum-iridium cylinder kept in France. In 2019, it was redefined using fundamental physical constants, specifically the Planck constant, making it more precise and universal.

Kilograms are universally used for measuring body weight, food quantities, luggage weight, and in scientific applications. It's the standard unit for mass in most countries worldwide, used in commerce, medicine, sports, and engineering. All other metric mass units are derived from the kilogram.