GLOSSARY · GOLD & METALS
What is troy ounce?
A troy ounce is the standard unit for precious metals, equal to about 31.10 grams — roughly 10% heavier than the ordinary avoirdupois ounce.
What it means
All gold pricing is per troy ounce, so the XAUUSD quote is the dollar cost of 31.10 grams. The distinction from a normal ounce is not trivia: confusing the two produces a 10% error in any conversion between the quoted price and a physical weight.
Why it matters
The standard contract of 100 troy ounces is what makes gold arithmetic convenient in a trading account. One standard lot is 100 ounces, so a $1.00 move in the quote is $100, and at the 0.01 minimum a $1.00 move is exactly $1.00.
What this changes in practice
That one-to-one correspondence at the minimum lot is genuinely useful when reasoning about risk. It means a stop expressed in dollars of gold price is immediately a stop in dollars of account, per micro lot — no conversion, no pip convention to resolve. See the pip value calculator for the full picture.
How many ounces of silver one troy ounce of gold has bought since 1971 is in the gold-silver ratio, tested.
Related terms
- XAUUSDXAUUSD is the ticker for spot gold priced in US dollars, quoting the cost of one troy ounce and …
- Contract sizeContract size is how many units of the underlying instrument one standard lot represents, and it…
- Micro lotA micro lot is one hundredth of a standard lot — 0.01 in the order ticket — and is the smallest …
- PipA pip is the conventional unit of price movement for an instrument, but on gold the convention i…
- Gold futuresGold futures are exchange-traded contracts to buy or sell gold at a set price on a future date. …
Educational information only, not financial advice. Trading leveraged products carries substantial risk of loss. Last updated 2026-09-09.