Ounce

Ounce (abbreviated oz) is a unit of mass that has several definitions. Most commonly it refers to the weight of approximately 28 grams.

Etymology

The name ounce comes from the Latin worduncia. It was a unit of weight, approximately 1/12 of the Roman pound (27.264 g).

Ounce Units

Ounce can refer to different standards of weight.

Ounce Variant

Weight in Grams

International avoirdupois ounce

28.3495231

International troy ounce

31.1034768

Apothecaries' ounce

Maria Theresa ounce

28.0668

Spanish ounce

28.75

Dutch metric ounce

100

Chinese metric ounce

50

Avoirdupois ounce is the most commonly used today. In 1958 the United States and the countries of the Commonwealth of Nations defined the international avoirdupois ounce as 0.45359237/16 kg (28.349523125 g). Today the ounce is the most commonly used measure of weight in the USA. From January 1, 2000 it is no longer a legal unit of measure in the United Kingdom, but is still very familiar, especially among older people.

Precious metals are traditionally priced in troy ounces.