One ounce (from the Latin uncia one twelfth, originally a Roman Libra, now mostly one-sixteenth of a pound, symbol ℥ ) is a non-metric unit of mass. The unit symbol is oz. ( from Italian onza ), the ounce English name.

Various ounces

Different notations are known for the ounce.

  • Okka: a measure in Hungary, Slavonia and Croatia.
  • Occa, Oka, Ocka: measure of capacity in Wallachia
  • Okka, Oka, Occa, Ocka: Turkish trade weight
  • Unzye: Polish ounce
  • Onca, Once, Onciam Ounce
  • Onca, Onça: Spanish, Portuguese and Brazilian weight
  • Ling, Lyang: Chinese ounce
  • Wakea, Waki (also Vakea, Vaki ): gold ounce in Abyssinia
  • Okkia: Silver coins in Morocco

Ordinary ounce

The ordinary ounce ( avoirdupois ounce English internationally ) with the unit symbol oz. is often used in some countries for food ( in Germany not permitted). It amounts to the equivalent of about 28.35 grams.

Pharmacist - ounce

The pharmacist - ounce (English Apothecaries Ounce) with the unit symbol or ℥ oz. ap. is used in medicines and chemicals and is the equivalent of about 31.1 grams.

Troy ounce

The troy ounce ( engl. Troy Ounce) with the unit symbol oz. tr is used for precious metals. Your weight is the pharmacist - ounce ( 1 oz.tr. = 31.1034768 grams ), but only refers to the precious metal content. The weight of any impurities is therefore deducted from the total weight. The gold, silver, platinum and palladium prices are quoted in U.S. dollars per troy ounce.

Fluid ounce

The fluid ounce ( engl. fluid ounce ) with the unit symbol fl oz is a unit of volume for liquids. The measure is used for example in measuring of perfume or soft drinks use, and it is printed on the bottle label. A fluid ounce equivalent in the United Kingdom and many countries of the Commonwealth 1/160 of a gallon after imperial system of measurement (about 28.4131 cm ³) and in the United States 1/128 of a gallon of US-style system of measurement (about 29.5735 cm ³).

Definition and conversion


  • In the Netherlands ons an unofficial but widely used unit of mass. 1 corresponds ons today 100 g
  • Formerly ounce also a name for the jaguar (Panthera onca; Portuguese Onça ) and the Irbis ( Uncia uncia ).