What is Fool's Gold made of?
In the world of minerals, few can charm the untrained eye quite like Fool's Gold.
The short answer
There are 31.1 grams in an ounce of gold (31.1035g to be exact). That's because gold is weighed in troy ounces, not standard (imperial) ounces.
A standard ounce, the kind used for food and post, is 28.35 grams. So a troy ounce of gold is about 2.75 grams heavier.
What is a troy ounce?
A troy ounce is the unit used to weigh gold, silver, platinum and palladium all over the world. It's often written as "oz t" or "ozt".
When you see a gold price "per ounce", it almost always means per troy ounce. The live gold price, bullion coins and gold bars all use it.
In the UK, the troy ounce is still a legal unit of trade, but only for gold, silver and other precious metals. This is set out in section 8 of the Weights and Measures Act 1985.
Troy ounce vs standard ounce
| Unit | Grams | Used for |
|---|---|---|
| Troy ounce | 31.1035g | Gold, silver, platinum and palladium |
| Standard (avoirdupois) ounce | 28.3495g | Food, post and everyday items |
A troy ounce is almost 10% heavier than a standard ounce.
Here's an odd fact. A troy pound is lighter than a standard pound. That's because a troy pound has 12 ounces (373.24g), while a standard pound has 16 ounces (453.59g).
Gold weight conversion table
| Weight | Grams | Troy ounces |
|---|---|---|
| 1 gram | 1g | 0.032 oz t |
| 1 pennyweight (dwt) | 1.56g | 0.05 oz t |
| 1/10 troy ounce | 3.11g | 0.1 oz t |
| 1/4 troy ounce | 7.78g | 0.25 oz t |
| 1/2 troy ounce | 15.55g | 0.5 oz t |
| 1 troy ounce | 31.10g | 1 oz t |
| 100 grams | 100g | 3.22 oz t |
| 10 troy ounces | 311.03g | 10 oz t |
| 1 kilo | 1,000g | 32.15 oz t |
How much is an ounce of gold worth today?
Right now, one troy ounce of pure gold is worth £3,031.84 at the live market price. That works out at £97.48 per gram.
Most jewellery isn't pure gold, so it's worth less per gram. For example, a troy ounce (31.1g) of 9ct gold is worth £1,136.94. Use our scrap gold calculator to work out what your own gold is worth, or see the gold prices we pay.
How much gold is in a 1oz gold coin?
A 1oz gold coin contains one troy ounce of pure gold. But the coin itself can weigh more. That's because some coins are mixed with other metals to make them harder.
| Coin | Total weight | Pure gold |
|---|---|---|
| 1oz Gold Britannia, The Royal Mint (24ct, 2013 onwards) | 31.21g | 31.10g (1 oz t) |
| 1oz Krugerrand (22ct) | 33.93g | 31.10g (1 oz t) |
| Full Sovereign (22ct) | 7.98g | 7.32g (0.24 oz t) |
Gold Traders currently pays 95.2% of the live gold price for UK gold bullion coins, such as Britannias and Sovereigns, and 94.2% for other bullion coins, such as Krugerrands. Find out more about selling gold coins, or browse our 1oz gold coins for sale.
Why is gold weighed in troy ounces?
The troy system is centuries old. It's thought to take its name from Troyes, a market town in France, where merchants met to trade in the Middle Ages.
Troy weights have been used for precious metals in Britain for centuries. Today, gold is priced in troy ounces on the major markets in London and New York, so dealers all over the world use the same measure.
Further reading
- Are you worth your weight in gold?
- How did gold get its name?
- How much gold is in the human body?
- How much gold is in a gold medal?
- Is gold magnetic?
Reviewed by Jon White, founder of Gold Traders
Last reviewed:
Jon founded Gold Traders in 2008. Gold Traders was the first precious metals company in the UK to gain Trading Standards accreditation through the Buy With Confidence scheme. Jon also campaigns for regulation of the UK precious metals buying market. Find out more about us.
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