How Many Grams in a Troy Ounce?
The exact conversion used by every gold dealer, mint, and precious metals exchange in the world.
Troy Ounce Conversion Reference
All the essential precious metals weight conversions in one place.
| Conversion | Value | Notes |
|---|---|---|
| 1 troy oz → grams | 31.1035 g | Universal precious metals standard |
| 1 gram → troy oz | 0.032151 ozt | Divide grams by 31.1035 |
| 1 troy oz → pennyweights | 20 dwt | Used for gold jewelry by many dealers |
| 1 pennyweight → grams | 1.5552 g | dwt = 1/20 troy oz |
| 1 troy oz → kilograms | 0.0311035 kg | Used for large bar weights |
| 1 avoirdupois oz → grams | 28.3495 g | NOT the same as troy oz — 9.7% lighter |
| 1 troy pound → grams | 373.24 g | 12 troy oz (not 16 like avoirdupois) |
Troy Oz ↔ Gram Converter
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Why Gold Uses Troy Ounces
The troy weight system dates back to medieval trade fairs in Troyes, France — one of the most important commercial centers of 12th and 13th century Europe. Merchants needed a consistent, trusted weight standard for precious metals transactions across different regions and currencies.
One key difference from everyday weights: a troy pound contains only 12 troy ounces (not 16 like the avoirdupois system used for food and goods). This means a troy pound (373.24g) is actually lighter than an avoirdupois pound (453.59g), even though a troy ounce (31.10g) is heavier than an avoirdupois ounce (28.35g).
The British Royal Mint adopted troy weights officially in 1527, and the standard spread globally through British colonial trade networks. Today, the London Bullion Market Association (LBMA), COMEX futures exchange, and every major gold and silver market in the world quotes prices in troy ounces. Understanding this conversion is fundamental to calculating any precious metals value correctly.
Common Coin & Bar Weights
Reference weights for the most commonly traded coins and bars in North America.
| Item | Troy Oz | Grams |
|---|---|---|
| American Silver Eagle | 1.000 | 31.1035 |
| American Gold Eagle (1 oz) | 1.0909 | 33.93 |
| Morgan Silver Dollar | 0.7734 | 24.057 |
| 1 oz Gold Bar | 1.000 | 31.1035 |
| 10 oz Silver Bar | 10.000 | 311.035 |
| 100g Gold Bar | 3.215 | 100.000 |
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