Kelly Criterion Calculator

Find your optimal position size using the Kelly formula

Uses & Examples

When to Use This Tool

Optimizing position sizing based on your actual win rate and avg win/loss
Determining if you're over-betting or under-betting relative to your edge
Using Half Kelly for a more conservative approach (most traders prefer this)
Recalculating your optimal bet size as your stats change month to month

Worked Example

Worked Example

Win rate: 55% | Avg win: $500 | Avg loss: $300

Win/loss ratio: $500 ÷ $300 = 1.67

Kelly % = 55% − (45% ÷ 1.67) = 55% − 26.9% = 28.1%

Half Kelly (safer): 14.1% of account per trade

On a $10,000 account, risk $1,410 per trade.