The kilogram (kg) is the base unit of mass in the International System of Units, defined by the Planck constant since 2019. It is the most widely used mass unit globally for body weight, grocery items, and shipping, appearing on scales in homes and markets everywhere. One kilogram equals roughly 2.2046 pounds.

The pound (lb) is an imperial unit of mass equal to exactly 0.45359237 kilograms, serving as the primary weight unit in the United States and parts of the British Commonwealth. Body weight, gym equipment, and packaged goods in America are almost always labeled in pounds. One pound equals 16 ounces or roughly 0.4536 kilograms.