Forex Kelly Criterion Calculator
Optimize your position sizing with the Kelly Criterion formula to maximize long-term account growth while managing risk based on your win rate and risk-reward ratio.
Risk Management
Position Sizing
Money Management
Calculate Optimal Position Sizing using Kelly Criterion
%
Your historical win percentage (e.g., 60 for 60%)
R
Average profit/loss ratio (e.g., 2 means average win is twice the average loss)
$
%
How much of your account you typically risk per trade
%
Percentage of the full Kelly to use (fractional Kelly)
Results
Full Kelly %
20.00%
Mathematically optimal but risky
Fractional Kelly %
10.00%
Recommended position size
Amount to Risk Per Trade
$1,000.00
Comparison to Current Risk
You should increase your risk by 8.00%
Expected Growth Rate
+2.6% per trade
Results are theoretical and assume your win rate and reward-risk ratio remain consistent.
Understanding the Kelly Criterion
- • The full Kelly formula is: K% = W - [(1-W)/R] where W is win rate and R is reward-to-risk ratio.
- • Most professional traders use a fractional Kelly (e.g., Half-Kelly) to reduce volatility.
- • The Kelly strategy maximizes logarithmic utility and long-term growth rate.
- • This approach assumes your edge (win rate and reward-risk ratio) remains consistent.