Why Position Sizing Matters More Than Entry Signals
A common misconception among retail traders is that finding the "perfect" entry signal is the key to profitability. In reality, proper position sizing determines whether you survive long enough for your edge to work. Professional traders say: "Position sizing makes or breaks traders, not entries."
The Three Core Rules of Position Sizing
Rule 1: Risk Same Percentage Per Trade - Every trade should risk the same percentage of your account (typically 1-2%). This ensures your account grows proportionally and you don't over-leverage after wins.
Rule 2: Never Risk More Than 2% Per Trade - Risking more than 2% per trade is excessive. If you experience a 5-loss streak (common for any trader), you'd lose 10%+ of account. This creates forced liquidation scenarios.
Rule 3: Total Daily Risk Should Not Exceed 5% - Even if each trade risks only 1%, trading 10 trades that all lose means 10% daily loss. Limit total daily risk by planning maximum trades per day.
The Mathematical Edge
Proper position sizing creates mathematical advantages:
Trader A: $10,000 account, wins 55% of trades (average trader), risks 2% per trade
- Year 1 profit: ~$15,000 (50% return)
- Year 2 profit: ~$25,000 (52% of $50,000)
- Year 3 profit: ~$40,000 (51% of $90,000)
Trader B: $10,000 account, same 55% win rate, risks 5% per trade
- Year 1: Likely hits 20%+ drawdown and quits or resets
- Account never compounds because overleveraging forces exits
Calculating Position Size Step-by-Step
- Choose account risk %: Start with 1% (conservative). Example: $10,000 × 1% = $100 risk per trade
- Determine stop loss distance: Based on your setup, where's your logical stop? Example: 50 pips
- Calculate pip value per lot: For EUR/USD: roughly $8 per pip per standard lot
- Calculate position size: Risk ($100) ÷ (Stop pips (50) × Pip value ($8)) = 0.25 lots
Position Sizing During Account Drawdown
Smart traders reduce position size during losing streaks:
- After 1 loss: Trade normal size
- After 2 consecutive losses: Reduce to 75% of normal size
- After 3 consecutive losses: Reduce to 50% of normal size
- After 4 consecutive losses: Stop trading and reassess strategy
This prevents catastrophic account blowups during inevitable losing periods.
Position Sizing for Different Trade Types
Scalp Trades (5-20 pip targets): Use micro position sizes (0.01-0.05 lots) due to frequent trades. Compounding effect requires consistency.
Swing Trades (100+ pip targets): Use standard sizing (0.1-1 lot) since you trade less frequently. Fewer trades mean you need adequate position size for profits.
Breakout Trades (volatile): Use tighter stops so position size can be slightly larger. Breakout volatility requires wider stops, reducing position size.
The Kelly Criterion in Position Sizing
Advanced traders use the Kelly Criterion formula:
This mathematically optimal formula ensures maximum account growth. However, most traders use a fraction (half-Kelly) to be conservative.
FAQ
A: Start with 1%. Only move to 2% after proving profitability for 6+ months consistently. Most professionals use 1%.
A: Experienced traders do this, but beginners shouldn't. Stick to consistent sizing until you have 1+ year of trading history.