Troy Ounce
Also: Fine Ounce, oz t, ozt, Ounce (precious metals)
The globally standard unit of weight in precious metal trading: one troy ounce equals exactly 31.1034768 grams of pure precious metal.
The troy ounce (abbreviated oz t or ozt) is the internationally recognised unit of measurement in which gold, silver, platinum, and palladium are traded. One troy ounce equals exactly 31.1034768 grams. Importantly: the troy ounce always refers to the quantity of pure precious metal, not the gross weight of a piece of jewellery or a coin.
Troy Ounce Is Not the Same as Ounce
In everyday life we encounter the avoirdupois ounce of around 28.35 grams – used for food, for example. The troy ounce used in the precious metal market is heavier and traces its origins to the medieval weight system of the French city of Troyes. When comparing prices, one should therefore look carefully: a "price per ounce" in the gold trade almost always means the troy ounce of 31.1035 grams.
Why the Troy Ounce Is So Important for Pricing
The current gold price and the silver price are quoted on world markets in US dollars per troy ounce. To move from there to the value of a specific bar or coin, one converts to grams:
- 1 troy ounce = 31.1034768 g
- 1 gram = 0.0321507 troy ounces
- 1 kilogram = 32.1507 troy ounces
A classic 100-gram gold bar therefore contains around 3.215 troy ounces of fine gold. The exact equivalent in euros can most quickly be calculated with the gold calculator or – for any unit – with the unit converter.
Troy Ounce in Investment Coins
Many well-known investment coins such as the Krugerrand, the Maple Leaf, or the Vienna Philharmonic contain exactly one troy ounce of fine gold. For coins with a copper alloy (such as the Krugerrand), the total weight is higher than 31.1 grams because the alloyed metal is added – but the fine gold content remains exactly one ounce. In addition to the full ounce, smaller denominations are also common: 1/2 oz, 1/4 oz, 1/10 oz, and sometimes 1/20 oz.
In Brief
The troy ounce is the pivotal point of every price quotation in the precious metals market. Anyone familiar with it can effortlessly convert world market prices, bar weights, and coin denominations – and immediately recognise whether an offer is fairly priced.