The Golden Rule
Never risk more than 1-2% of your account on a single trade. This is non-negotiable. A 1% risk means 100 consecutive losses to blow your account. A 5% risk means 20. The math is clear — smaller risk per trade equals longer survival and more opportunities to profit.
The Position Sizing Formula
Position Size = (Account Balance × Risk Percentage) ÷ (Entry Price − Stop Loss Price)
Example: $10,000 account, 1% risk ($100), entry at $2,000, stop at $1,950 (50-point stop). Position size = $100 ÷ $50 = 2 units.
Forex Lot Sizing
For forex: Lot Size = Risk Amount ÷ (Stop Loss in Pips × Pip Value). For EUR/USD with $100 risk and 20-pip stop: Lot Size = $100 ÷ (20 × $10) = 0.5 lots. Use our free position size calculator to compute this instantly.
Adjusting for Volatility
When ATR is high, your stop loss is wider, so your position size decreases automatically with this formula. When ATR is low, stops are tighter and position size increases. This naturally adjusts your exposure to market conditions.