Quick answer
One troy ounce is 31.1 grams. One regular (avoirdupois) ounce is 28.35 grams. Precious metals are always priced per troy ounce.
Two different ounces
| Grams | Used for | |
|---|---|---|
| Troy ounce (ozt) | 31.1035 | Gold, silver, platinum, palladium |
| Regular ounce (oz) | 28.3495 | Food, packages, most everyday weights |
A troy ounce is about 9.7% heavier than a regular ounce.
Why it matters
The spot price is quoted per troy ounce. If you weigh your gold in regular ounces and multiply by the spot price, you’ll be off by about 10%.
For example, a chain that weighs 1 regular ounce on a kitchen scale is only 0.91 troy ounces.
Pennyweight
Many US gold buyers quote prices per pennyweight (dwt). There are 20 pennyweights in a troy ounce, and one pennyweight is 1.555 grams.
Converting
Use the weight converter to switch between grams, pennyweight, troy ounces and regular ounces, or pick the unit right in the calculator.
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