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 ounce (oz) is an imperial unit of weight equal to about 28.35 grams, widely used in the United States for food packaging, postal services, and precious metals. In the kitchen, recipes often list ingredients in ounces, and gold and silver are traded in troy ounces. One ounce equals approximately 28.35 grams.