Position Sizing Strategies for Traders
Beyond the basic formula lies a world of sophisticated position sizing techniques. Learn the strategies used by hedge funds and professional traders.
Use our calculator to implement any of these sizing strategies.
Open Position Size CalculatorWhy Position Sizing Strategy Matters
Two traders with identical entry and exit signals can have vastly different results based solely on their position sizing strategy.
1. Fixed Fractional Position Sizing
Fixed fractional is the most widely used professional method. You risk a fixed percentage of your current account balance on every trade.
Position Size = (Account × Risk%) ÷ Risk Per UnitHow It Works
- Choose a fixed risk percentage (typically 1-2%)
- Calculate risk amount from current account balance
- Position size automatically scales with account growth/decline
Example:
Account: $50,000 → Risk 1% = $500
After growth to $60,000 → Risk 1% = $600
After drawdown to $40,000 → Risk 1% = $400
Automatic position scaling protects capital during drawdowns
Best For:
Most traders. This should be your default strategy.
2. Kelly Criterion
The Kelly Criterion calculates the optimal position size to maximize long-term growth rate while avoiding ruin.
Kelly % = W - [(1-W) / R]Where W = Win Rate, R = Win/Loss Ratio
Use Fractional Kelly
Most professionals use "half-Kelly" (50%) or "quarter-Kelly" (25%). Half-Kelly achieves 75% of the growth rate with much smoother equity curves.
3. Volatility-Based Position Sizing
Adjusts position size based on the asset's current volatility using the ATR indicator.
Position Size = (Account × Risk%) ÷ (ATR × ATR Multiplier)4. Fixed Ratio Position Sizing
Developed by Ryan Jones, fixed ratio increases position size only after achieving a specific profit target (delta).
Comparing the Strategies
| Strategy | Complexity | Risk Level | Best For |
|---|---|---|---|
| Fixed Fractional | Low | Moderate | Everyone |
| Kelly Criterion | Medium | High (if full) | Experienced traders |
| Volatility-Based | Medium | Moderate | Multi-asset traders |
| Fixed Ratio | High | Conservative | Futures traders |
Our Recommendation
For most traders, fixed fractional position sizing at 1-2% risk is the optimal choice.
The Most Important Rule
Whatever strategy you choose, the key is consistency. Switching between methods mid-drawdown will hurt your results.