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A troy ounce is 31.1035 grams. The ounce on a kitchen scale is 28.35. Confusing the two overstates a holding by about 10%, and it is the most common mistake on this subject.
The gold price shown was recorded when this page was published. Figures calculated from it appear once the live price loads, so nothing here is worked out from a number the market may have left behind.
Convert a weight
The kitchen-scale ounce is 28.3495 grams, not 31.1035. Weighing bullion on one and reading the number as troy overstates a holding by about 10%.
Pure metal at spot. Alloys are worth their share of it.
The same weight, every unit
| Grams | 31.1035 |
| Troy ounces (ozt) | 1 |
| Kilograms | 0.0311 |
| Tolas | 2.6667 |
| Pennyweights (dwt) | 20 |
| Spot value as goldPure metal, at the live price | — |
Troy against everyday ounces
A troy ounce is 31.1035 grams; the avoirdupois ounce on a kitchen or postal scale is 28.3495. Precious metal has been quoted in troy ounces for centuries, so every spot price, every coin's stated weight and every dealer's listing means troy.
Confusingly, a troy POUND is lighter than a normal one — twelve troy ounces rather than sixteen — so a "pound of silver" is ambiguous and worth avoiding entirely.
Where the other units come from
The tola is three-eighths of a troy ounce exactly and is still the trading unit across South Asia and the Gulf. The pennyweight is one twentieth, abbreviated dwt from the Latin denarius, and is what most American scrap buyers quote in.
Both are definitions rather than measurements, so nothing here is approximated. See gold price per tola for the price side.
Common questions
- Is a troy ounce the same as a normal ounce?
- No. A troy ounce is 31.1035 grams and the avoirdupois ounce on a kitchen or postal scale is 28.3495 grams, so a troy ounce is about 10% heavier. Every precious metal spot price, coin weight and dealer listing means troy ounces.
- Is a troy pound sixteen troy ounces?
- No — a troy pound is twelve troy ounces, so it is lighter than an ordinary pound despite the ounce being heavier. "A pound of silver" is genuinely ambiguous and is worth avoiding entirely; quote troy ounces or grams instead.
- How many grams are in a tola and a pennyweight?
- A tola is 11.6638 grams, three-eighths of a troy ounce. A pennyweight is 1.5552 grams, one twentieth of a troy ounce. Both are definitions rather than measurements, so converting between them and troy ounces is exact.