XAUUSD Lot Size Explained
What one lot of gold is, what 0.01 lot is worth per $1 move, and how to size a XAUUSD position from your account balance, risk per trade and stop distance.
By the AURAX teamPublished 4 min read
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On most brokers one standard lot of XAUUSD is 100 troy ounces, so it gains or loses $100 for every $1 the gold price moves. 0.10 lot is 10 ounces ($10 per $1), and the usual minimum of 0.01 lot is 1 ounce ($1 per $1). To size a trade, divide the money you are willing to lose by what the position loses if the price reaches your stop.
lots = risk in $ ÷ (stop distance in $ × contract size)
- risk in $ = account balance × risk per trade (e.g. 1%)
- stop distance = gap between entry and stop-loss, in dollars of gold price
- contract size = ounces per lot, usually 100
Part of the XAUUSD trading guide.
Standard, mini and micro lots
| Lots | Name | Ounces | Per $0.01 | Per $1 | Per $10 |
|---|---|---|---|---|---|
| 1.00 | Standard | 100 | $1.00 | $100 | $1,000 |
| 0.10 | Mini | 10 | $0.10 | $10 | $100 |
| 0.01 | Micro | 1 | $0.01 | $1 | $10 |
Two things follow from the table. A $0.01 change in price (one point on a two-decimal quote) is worth exactly $1 on one lot, which makes the arithmetic easy. And because gold regularly moves tens of dollars in a day, a single standard lot swings by thousands of dollars in ordinary conditions.
Sizing a position from risk
Professional sizing starts from how much you are prepared to lose, not from how much you want to make. The steps:
Choose a risk per trade
A fixed fraction of the balance — 0.5% to 2% is the range most risk guidance works in.
Decide where the trade is wrong
Place the stop where the idea is invalidated, not where the loss feels comfortable. Measure it in dollars of price.
Divide
Risk in dollars ÷ (stop distance × 100) = lots. Round down to the broker's lot step.
Notice what happens with a wider stop: at $12 the same $100 buys only 0.08 lots. The stop distance, not the account size alone, decides the position.
Include costs and slippage
The formula gives the loss if price reaches the stop exactly. In practice the loss is a little larger:
- Spread: a buy opens at the ask and closes at the bid. A $0.30 spread on 0.16 lots is another $4.80. See XAUUSD spread explained.
- Slippage: in a fast market a stop fills beyond its level. Around major news the gap can be several dollars.
- Commission, if your account type charges one.
A simple habit: add the typical spread to the stop distance before dividing.
Check the margin too
Risk-based sizing tells you what you can afford to lose. Margin tells you what the broker needs you to put up to hold the position at all:
margin = lots × contract size × price ÷ leverage
- 0.16 lots × 100 × $3,000 ÷ 100 (1:100) = $480
If margin for the position is a large share of your equity, a modest move can push the account toward a margin call before the stop is reached. Margin and free margin and leverage cover this in detail.
When one trade becomes several
The formula assumes one position with one stop. Strategies that add positions — scaling in, averaging down, grids — change the maths completely: exposure grows as price moves against you, and the loss is the sum across every open position.
A grid that starts at 0.01 lot and doubles each level is at 1.28 lots on its eighth position — 128 times where it started, with 2.55 lots open in total. How lot multipliers change grid risk works through it level by level.
Sources
- Margin calculation (Forex and CFD) — MetaQuotes — MetaTrader 5 Help
Educational content, not financial advice. Trading gold and other leveraged products carries a high level of risk, including the possible loss of some or all of your capital. Automated strategies do not guarantee profit, and past or simulated performance is not indicative of future results. Risk disclosure.