Gold Coin Weights
Gold coins may state a fine-gold size while weighing more because of alloy metal. Historic denominations add another layer: their face values do not reveal exact gold content.
In This Guide
Modern Bullion Coins
| Coin | Fine Gold (oz t) | Gross Weight (g) | Fineness | Diameter (mm) |
|---|---|---|---|---|
| American Gold Eagle 1 oz | 1.0000 | 33.931 | 0.9167 | 32.70 |
| American Gold Eagle 1/2 oz | 0.5000 | 16.966 | 0.9167 | 27.00 |
| American Gold Eagle 1/4 oz | 0.2500 | 8.483 | 0.9167 | 22.00 |
| American Gold Eagle 1/10 oz | 0.1000 | 3.393 | 0.9167 | 16.50 |
| American Gold Buffalo 1 oz | 1.0000 | 31.103 | 0.9999 | 32.70 |
| Krugerrand 1 oz | 1.0000 | 33.930 | 0.9167 | 32.69 |
| British Sovereign | 0.2354 | 7.988 | 0.9167 | 22.05 |
Common Pre-1933 U.S. Gold
| Coin | Fine Gold (oz t) | Gross Weight (g) | Fineness | Diameter |
|---|---|---|---|---|
| U.S. $2.50 Quarter Eagle | 0.12094 | 4.18 | 0.900 | Varies |
| U.S. $5 Half Eagle | 0.24187 | 8.359 | 0.900 | Varies |
| U.S. $10 Eagle | 0.48375 | 16.718 | 0.900 | Varies |
| U.S. $20 Double Eagle | 0.96750 | 33.436 | 0.900 | Varies |
Fine Weight vs. Gross Weight
Fine weight counts gold alone. Gross weight counts the entire alloy. A one-ounce Gold Eagle contains one full troy ounce of gold but weighs approximately 33.931 grams because silver and copper are added.
Fractional Comparisons
One half-ounce coin contains 0.5 troy ounce; a quarter-ounce contains 0.25; a tenth-ounce contains 0.1. A British Sovereign contains about 0.2354 troy ounce and is not exactly a quarter-ounce coin.
Historic-Coin Caution
Pre-1933 specifications vary by denomination, type, and period. Wear, rare varieties, counterfeits, and cleaning can affect value beyond gold content.
- Do not infer gold content from face value.
- Do not confuse gross and fine weight.
- Do not clean historic gold.
- Do not treat approximate reference figures as authentication.
Frequently Asked Questions
Why does a one-ounce Gold Eagle weigh 33.931 grams?
It contains one troy ounce of gold plus silver and copper alloy.
Is a Sovereign one-quarter ounce?
No. A full Sovereign contains approximately 0.2354 troy ounce of gold.
Does old gold always carry a collector premium?
No. Date, mint, variety, condition, and demand determine any premium beyond gold value.
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Use fine-gold content for melt value, gross weight for verification, and numismatic knowledge for historic-coin premiums.