JustChartsTroy Ounce vs Ounce: How Many Grams Is 1 Ounce of Gold?
One troy ounce — the unit used for gold, silver and other precious metals — is 31.1035 grams. A regular (avoirdupois) ounce, used for food and everyday goods, is 28.3495 grams. So a troy ounce is about 9.7% heavier, and when a gold price is quoted “per ounce” it always means per troy ounce.
Key facts
- 1 troy ounce
- 31.1035 g
- 1 avoirdupois ounce
- 28.3495 g
- Difference
- troy ounce ≈ 9.7% heavier
- 1 kg
- 32.15 troy oz (35.27 regular oz)
- Troy pound
- 12 troy oz (not 16)
Why does gold use a different ounce?
The troy system of weights dates back to medieval European trade fairs and became the standard for precious metals. Today the LBMA, COMEX and virtually every dealer quote gold and silver per troy ounce, while everyday goods use the avoirdupois ounce.
Conversion table
| Amount | Grams | Troy ounces |
|---|---|---|
| 1 troy ounce | 31.1035 | 1 |
| 1 regular ounce | 28.3495 | 0.9115 |
| 1 gram | 1 | 0.03215 |
| 10 grams | 10 | 0.3215 |
| 100 grams | 100 | 3.215 |
| 1 kilogram | 1,000 | 32.1507 |
How to convert a gold price per ounce to per gram
Price per gram = price per troy ounce ÷ 31.1035
At $2,400 per ounce, gold costs about $77.16 per gram, or $77,162 per kilogram. Local jewellery prices are usually higher because of making charges, taxes and dealer margins.
Other gold units you might see
- Tola (South Asia and the Gulf): 11.6638 g
- Tael (Hong Kong): 37.429 g; other taels vary by region
- Baht (Thailand, for gold): about 15.2 g
For trading, everything is in troy ounces — see how many lots 1 kg of gold is.
Frequently asked questions
How many grams is 1 ounce of gold?
One troy ounce of gold is 31.1035 grams. Gold is never priced in regular 28.35-gram ounces.
Is a troy ounce bigger than an ounce?
Yes. A troy ounce (31.1 g) is about 9.7% heavier than a regular avoirdupois ounce (28.35 g).
How many troy ounces are in a kilogram?
There are 32.1507 troy ounces in one kilogram.
Is silver also measured in troy ounces?
Yes. Silver, platinum and palladium are all priced per troy ounce.
Put it into practice
Live charts, an economic calendar and trading calculators — free with a JustCharts account.
See the live gold price per troy ounceThis article is for education only and is not financial advice. Trading leveraged products carries a high risk of losing money. Contract sizes, trading hours and leverage limits vary by broker and country — always check your own broker’s specifications.