The troy ounce is the standard unit of measurement for precious metals worldwide. It is not the same as a regular (avoirdupois) ounce.
Troy vs. Standard Ounce
| Measurement | Weight in Grams |
|---|---|
| **1 Troy Ounce** | 31.1035 grams |
| **1 Standard Ounce** | 28.3495 grams |
Origin
The troy system dates back to the Middle Ages and is named after Troyes, France, a major trading hub where the standard was established. It has been used for precious metals trading for centuries.
Why It Matters
When you buy a "1 oz" gold coin or bar, you are receiving 31.1 grams of metal — not 28.3 grams. Always confirm that weights are quoted in troy ounces when comparing prices.