Convert ounces to kilograms
Please provide values below to convert ounce [oz] to kilogram [kg], or vice versa.
Ounce
Definition: The ounce (symbol: oz) is a unit of mass in the imperial and United States customary systems of measurement. The avoirdupois ounce, which is most commonly used, is defined as exactly 28.349523125 grams.
History/origin: The term "ounce" is derived from the Roman unit "uncia," which was one-twelfth of a Roman pound (libra). Over time, various definitions of the ounce arose in different parts of Europe.
There are two main types of ounces: the avoirdupois ounce and the troy ounce. The avoirdupois ounce is used for most everyday purposes, including measuring food, while the troy ounce is used for measuring precious metals.
Current use: The ounce is primarily used in the United States and other countries that use US customary units. It is commonly used to measure food, packaged goods, and other everyday items.
Kilogram
Definition: A kilogram (symbol: kg) is the base unit of mass in the International System of Units (SI). It is defined by taking the fixed numerical value of the Planck constant h to be 6.62607015×10⁻³⁴ when expressed in the unit J⋅s, which is equal to kg⋅m²⋅s⁻¹.
History/origin: The kilogram was originally defined in 1795 as the mass of one liter (cubic decimeter) of water. In 1799, a platinum artifact was fabricated to represent the kilogram. This artifact, known as the International Prototype of the Kilogram (IPK), was stored at the International Bureau of Weights and Measures (BIPM) in Sèvres, France.
For nearly 130 years, the kilogram was defined as exactly the mass of the IPK. However, in 2019, the kilogram was redefined in terms of the Planck constant, making it based on invariant constants of nature rather than a physical artifact that could change over time due to contamination or wear.
Current use: The kilogram is used globally as the standard unit of mass in science, commerce, and everyday life in most countries that have adopted the metric system. It's used for measuring the mass of objects ranging from groceries to industrial materials to scientific specimens.