Kelly Criterion Calculator

Find the mathematically optimal fraction of your bankroll to wager based on your edge and odds.

Optimal Bet (Fractional Kelly)
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Full Kelly %
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Fractional Kelly %
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Edge
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Expected Growth Rate
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Expected Value / Bet
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P(Ruin) Approx
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Kelly Fraction Comparison

Kelly Criterion Formula

f* = (bp - q) / b

b = decimal odds - 1 (net odds)

p = probability of winning

q = probability of losing (1 - p)

f* = fraction of bankroll to bet

Many practitioners use fractional Kelly (often 1/2 or 1/4) to reduce volatility while still capturing most of the growth advantage.

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