Troy ounce

A troy ounce (abbreviation t oz) equals approximately 31.1 grams (which is equal to 480 grains).

It is the most commonly used measure of expressing the weight of precious metals today. Bullion coins are usually sold in troy ounces. A kilogram bullion bar contains 32.15 troy ounces.

  • Fine Ounce – a troy ounce of 99.5% pure gold.
  • Standard Ounce – a troy ounce of 22-karat gold (91.66% pure gold)
  • An Ounce of Gold – in modern times it is defined as 99.99% pure gold piece

Troy ounce is a part of a mass system known as the Troy weight system. It was developed in medieval times, as a system for weighing precious metals, gemstones or gunpowder. The name “troy” comes from the city of Troyes, located in northeastern France.