Kelly Criterion Calculator

How It Works

The Kelly Criterion determines the optimal fraction of your bankroll to wager, maximizing long-term growth while minimizing the risk of ruin.

Kelly % = (b × p − q) / b

Where b = decimal odds − 1, p = win probability, and q = 1 − p. The adjusted Kelly multiplies this by a fraction (commonly 0.25 for quarter Kelly) to reduce variance.

Wager = Bankroll × Adjusted Kelly %

If the Kelly percentage is negative, you have no edge and should not place the bet. Most professional bettors use quarter to half Kelly to reduce volatility.