Free tool
XAUUSD lot size calculator
Enter your balance, how much you are willing to lose and where your stop-loss is. The calculator gives the gold lot size that keeps the loss at the stop within that amount, rounded down to a lot your broker accepts.
Position size
0.10lots
10.00 oz
- Money at risk
- $100.00
- Of balance
- 1.00 %
- Per $1 move
- $10.00
- Target at 1:2
- $200.00
Risk includes commission; spread, slippage and gaps can add to it. Your broker's figures for contract size and margin always prevail.
How the gold lot size is calculated
The lot size is the money at risk divided by what one lot loses if the stop-loss is hit. For gold, one standard lot is usually 100 troy ounces, so a $1 move changes a 1.00 lot position by $100.
lot = risk ÷ (contract size × stop distance + commission per lot)
The result is rounded down to the lot step (usually 0.01), so the real risk never exceeds what you set. The money at risk shown is that of the rounded lot, including commission.
| Balance | $10,000 |
|---|---|
| Risk 1 % | $100.00 |
| Stop-loss distance | $10.00 per oz |
| Loss per 1.00 lot at the stop | 100 oz × $10 = $1,000 |
| Lot size | 100 ÷ 1,000 = 0.10 lot |
With a $7 round-turn commission the loss per lot becomes $1,007, the raw lot 0.0993, and the lot rounds down to 0.09: a real risk of $90.63, or 0.91 % of the balance.
Lot size, margin and stop-out
The lot size does not depend on the price of gold or on leverage; the margin does. Margin is the notional value divided by leverage: 0.10 lot at $4,000 is $40,000 of gold, which needs $80 of margin at 1:500. Enter an entry price to see the margin and the largest lot your balance allows.
Brokers can raise margin requirements for gold around news, rollover or weekends, and a stop-loss can fill worse than its price in fast markets. Check your platform before you trade. See the Risk Disclosure.
Questions
How do I calculate the lot size for gold (XAUUSD)?
Divide the money you are willing to lose by the loss per lot at your stop-loss. One standard lot of gold is usually 100 troy ounces, so a $1 move in price changes a 1.00 lot position by $100. With a $10,000 balance, 1 % risk ($100) and a $10 stop-loss distance: 100 ÷ (100 × 10) = 0.10 lot.
How much is a $1 move in gold per lot?
On a 100-ounce contract, a $1 move is worth $100 per 1.00 lot, $10 per 0.10 lot and $1 per 0.01 lot. Some brokers use a different contract size; check the contract specification in your trading platform and enter it in the calculator.
Why does the calculator use a stop distance in dollars instead of pips?
Brokers count gold pips differently: some call $0.10 a pip, others $0.01. A distance in dollars per ounce means the same thing everywhere, so the result does not depend on which convention your platform uses.
Why is the lot rounded down?
Lots are traded in steps, usually 0.01. Rounding down keeps the real risk at or below the amount you set, never above it. The calculator then shows the risk of the rounded lot, not the target.
Does commission change the lot size?
Yes. A round-turn commission per lot is part of what you lose if the stop-loss is hit, so it is added to the loss per lot before the lot is calculated. Spread and slippage can add to the loss as well.
Is this financial advice?
No. The calculator does arithmetic on the numbers you enter. It does not tell you whether, when or what to trade, and your broker's own figures for margin and contract size always prevail.
Aureus
The full calculator lives in Risk Forge
In Aureus, Risk Forge uses your broker's figures and live prices, adds spread, free margin and the stop-out price, warns when the stop-out comes before your stop-loss, and compares positions side by side.