Fixed Fractional Position Sizing: The Professional Standard
Risk a fixed percentage of your account on every trade. This simple rule, applied consistently, is the foundation of professional capital management.
The Core Principle
Fixed fractional position sizing means you risk a predetermined percentage of your current account equity on every trade — typically 0.5% to 2%. The critical word is "current" — not a fixed dollar amount, but a fixed percentage of whatever the account is worth at this moment.
The Full Calculation
Step 1: Risk amount = Account Equity × Risk % ($15,000 × 1% = $150)
Step 2: Stop loss in pips from your setup (e.g., 25 pips)
Step 3: Pip value per lot (EUR/USD standard lot = $10/pip)
Step 4: Lot size = Risk Amount ÷ (Stop Pips × Pip Value) = $150 ÷ $250 = 0.6 lots
Why Fixed Fractional Works
During drawdown, position sizes automatically decrease — slowing the rate of loss. During growth, sizes automatically increase — compounding gains. This natural scaling is the key advantage over fixed dollar sizing, which grows proportional risk during drawdowns and shrinks it during profits — the exact opposite of what serves the trader.
The Compounding Effect
At 1% risk per trade with positive expectancy, the compounding on a growing base is the primary long-term return driver. The per-trade returns are modest. The compounding is extraordinary over years. This is the mechanism that institutional traders exploit — not high-risk, high-return single trades.
Choosing Your Risk Percentage
- Accounts under $25,000 or high-variance strategies: 0.5–1%
- Accounts $25,000–$100,000 with tested positive expectancy: 1–1.5%
- Institutional or managed accounts: 0.25–1%
Fixed fractional sizing is boring to implement and extraordinary in its long-term impact. Boring is the goal.