XAUUSD Lot Size Calculator
Enter your balance, your risk and your stop-loss. Get the exact gold lot size in seconds, with the risk, the target and the margin to check before you click Buy or Sell.
- Free, no sign-up
- Runs in your browser
- Formula explained below
- Checked against a real prop firm trade
XAUUSD Lot Size Calculator
Estimates only. Spread, commission, slippage and your broker’s contract size can change the real result. See the methodology and the risk disclaimer. Nothing you type is sent to our servers.
The math behind the lot size
Gold moves in dollars, and most brokers define 1 lot as 100 ounces. That makes the math simple, and easy to check by hand.
The formula
Risk amount = Balance × Risk % Lot size = Risk amount ÷ (Stop-loss in $ × 100)
The result is rounded down to your lot step, so your real risk never goes above the amount you chose.
Worked example
$10,000 account, 1% risk, entry 2650.00, stop-loss 2640.00.
Risk amount = $10,000 × 1% = $100 Stop-loss = 2650 − 2640 = $10 Lot size = 100 ÷ (10 × 100) = 0.10 lot
If the stop is hit you lose about $100. With a 1:2 target, you make about $200.
What a $1 move is worth
| Lot size | Ounces | Per $1 move | $10 stop risks |
|---|---|---|---|
| 1.00 | 100 oz | $100 | $1,000 |
| 0.10 | 10 oz | $10 | $100 |
| 0.01 | 1 oz | $1 | $10 |
Brokers do not agree on what a “pip” is in gold. That is why the calculator works with the dollar distance and shows pips only as a reference. Read the full methodology.
Related tools: see what a pip, a point and a tick are worth on gold with the XAUUSD Pip / Point / Tick Value Calculator, size a trade on forex pairs or in another account currency with the Position Size Calculator, or check what one pip is worth on 18 pairs with the Pip Value Calculator.
Three mistakes that break a lot size
Typing the risk instead of the distance
The stop-loss field is the price gap between entry and stop, for example $18.61. It is not the money you want to risk. Mix them up and the lot size collapses.
Trusting the wrong contract size
Most brokers use 100 oz per lot, a few do not. Check your platform’s contract specification and update Broker settings if it differs.
Forgetting spread and minimum lot
Spread widens your real stop. And if the result is below your broker’s minimum lot, the smallest trade already risks more than you planned.
Tired of typing numbers before every trade?
The calculator is perfect for planning. But when price is moving, you do not want to switch tabs. Lot Architect brings the same formula onto your MetaTrader chart.
- Set entry, stop-loss and take-profit, and see them as lines on your chart
- Choose how you size the trade: Risk %, Risk USD or fixed Lots
- Live readout of position size, margin, risk and reward with the risk-to-reward ratio
- Long or Short, with Market, Limit and Stop orders from one panel
- The order button shows the exact lot before you send it
- Hide or show the chart lines with one key (H)
Lot Architect is my own product, sold on the MQL5 Market. If you buy it, I earn money. The free calculator stays free either way.
Frequently asked questions
What lot size should I use for gold?
How much is 0.01 lot of gold worth per $1 move?
Why does the calculator show a very small lot size?
Is 1 lot of gold always 100 ounces?
Does the calculator include spread and commission?
Is the calculator really free?
What is Lot Architect?
Which platforms does Lot Architect support?
Size every gold trade in seconds, right on your chart
Plan with the free calculator. Execute with Lot Architect on MT5 or MT4.
Sold on the MQL5 Market. See the disclosure for how this site earns money. Trading is risky and not financial advice: read the risk disclaimer.