Optimal Bet Sizing

Optimal Bankroll Management with Kelly Criterion

The Kelly Criterion is a mathematical formula that tells you the optimal percentage of your bankroll to wager based on your edge and the odds offered. It maximizes long-term growth while minimizing risk of ruin, making it the gold standard for bankroll management among professional bettors.

Many successful bettors use a fractional Kelly approach (1/4 Kelly or 1/2 Kelly) to reduce variance while still capitalizing on positive expected value opportunities. Our Kelly calculator helps you determine the perfect bet size for your edge, bankroll, and risk tolerance.

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Understanding Kelly Criterion

The Kelly Criterion is a mathematical formula used to determine optimal bet sizing based on your edge and bankroll. It maximizes long-term growth while minimizing risk of ruin.

Kelly % = (bp - q) / b
• b = decimal odds - 1
• p = your estimated win probability
• q = lose probability (1 - p)

Fractional Kelly: Most pros use 1/4 or 1/2 Kelly to reduce variance. Full Kelly can lead to large swings.