How to Size Your Forex Positions Correctly
The single most common way traders blow accounts isn't picking the wrong direction — it's trading the same lot size regardless of stop-loss distance. Here's the fix.
Position size (lots) = (account balance × risk %) ÷ (stop-loss in pips × pip value per lot). This keeps your dollar risk constant no matter how wide or tight your stop is.
Why stop-loss distance must drive position size
If you always trade 1 lot, a 10-pip stop risks $100 while a 50-pip stop risks $500 on the same pair — a 5x difference in risk for trades you may consider equally valid. Sizing by a fixed % of account risk removes this inconsistency entirely.
Worked example
$10,000 account, 1% risk = $100 risk budget. EUR/USD pip value is $10/standard lot. With a 25-pip stop-loss: lots = 100 ÷ (25 × 10) = 0.4 lots — trade exactly 0.4 standard lots to risk precisely $100 if the stop is hit.
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Frequently Asked Questions
What risk % should I use per trade?↓
Most risk-management guidance suggests 0.5%–2% of account balance per trade. Higher risk per trade means fewer losing trades needed to meaningfully damage the account.
Do I need to recalculate position size every trade?↓
Yes — since it depends on your current stop-loss distance and account balance (which changes as you win/lose), recalculating each time keeps risk genuinely consistent.