Position size calculator by risk percentage (forex and gold)
This is the calculator to use before every trade: instead of guessing “0.1 lot feels fine”, work backwards from the amount you are prepared to lose.
Formula
Lots = (balance × risk %) ÷ (stop loss in pips × value of 1 pip for 1 lot)
The value of 1 pip for 1 lot is 10 USD for EURUSD and other pairs quoted in USD, 10 USD for gold (1 pip = 0.10 USD), and it varies with the price for JPY pairs and crosses. See the pip value calculator.
Example 1: EURUSD
- Balance 1,000 USD, risk 2% → you accept losing 20 USD.
- Stop loss 25 pips; one pip on 1 lot = 10 USD.
- Lots = 20 ÷ (25 × 10) = 0.08 lot.
If the stop is hit: 0.08 × 25 × 10 = 20 USD, exactly 2% of the account.
Example 2: gold (XAUUSD)
- Balance 1,000 USD, risk 1% → 10 USD.
- Stop 5 USD away in price = 50 pips (1 pip = 0.10 USD).
- Lots = 10 ÷ (50 × 10) = 0.02 lot.
Example 3: cent account
- Deposit 100 USD = 10,000 USC, risk 2% → 200 USC.
- Stop loss 25 pips on EURUSD.
- Result: 0.8 lot on the cent account, i.e. 0.008 standard lot. The calculator assumes 1 cent lot = 0.01 standard lot; check your broker’s contract specifications.
Keep in mind
Price can jump past your stop on big news or at the weekly open (slippage), so the actual loss can be larger than the calculated amount.
FAQ
What percentage of my account should I risk per trade?
Many traders keep it to 1–2% per trade so a losing streak cannot drain the account. That is a common money-management habit, not investment advice; the right level is up to you.
Why is the result rounded down?
Brokers only accept sizes in steps of 0.01 lot. Rounding up would make you lose more than your chosen risk if the stop is hit, so the calculator always rounds down.
What if the result is below 0.01 lot?
With that balance and risk, the stop is too far away for the smallest trade size. Move the stop closer, skip the trade, or use a cent account.