A kilogram is a unit of mass or weight. It is equal to about 2.2 pounds or 1000 grams. The kilogram is the only SI unit with an SI prefix (“kilo-“) as part of its name, but it is normally written with a lower-case “k” (for example, kg).
A gram is a metric system unit of mass that equals about one seventh of a kilogram. The kilogram and the gram are not interchangeable in everyday usage because a mass expressed as “a kilogram” can be either a mass of 1,000 grams or one millionth of the Earth’s mass.
In the United States and other English-speaking countries, a pound (lb) is commonly used instead of the kilogram; however, this conversion is not exact because it does not take into account the difference between standard gravity on Earth (9.80665 m/s2) and standard gravity on the Moon (1.622 m/s2), which makes it more difficult to lift objects on the Moon than on Earth even though both bodies have approximately the same mass and diameter. In most countries outside the United States and Canada, no distinction between kilograms and pounds is made.
Last modified: August 9, 2022