The quick answer: a standard ounce is about 28.35 grams. But if you are weighing gold or silver, the answer is 31.1035 grams — because precious metals use a different ounce. Here is why.
The two ounces
| Ounce type | Grams | Used for |
|---|---|---|
| Standard (avoirdupois) | 28.3495 g | Food, mail, everyday goods |
| Troy | 31.1035 g | Gold, silver, platinum, palladium |
So a troy ounce is about 10% heavier than the ounce on your kitchen scale. That difference matters a lot when you are pricing metal: at $2,000 per troy ounce, that extra 2.75 grams is real money.
Where the troy ounce comes from
The troy system dates back to the medieval trade town of Troyes in France and became the standard for weighing precious metals. It survived precisely because consistency matters most where value is highest. When you read a live gold price or a silver price, it is always per troy ounce.
Handy gram conversions
- 1 standard ounce = 28.35 g
- 1 troy ounce = 31.1035 g
- 1 pound = 16 standard ounces = 453.592 g
- 1 kilogram = 32.15 troy ounces
For any other weight conversion, our unit converter has a dedicated weight category — including both ounce types where relevant.
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