Kelly Criterion Calculator

The Kelly criterion sets the stake that maximises the long-run growth rate of a bankroll, and it works out to the edge divided by the odds. Enter the price in decimal, American or fractional form, your own probability of winning, and what fraction of full Kelly you want to use; back come the stake, the expected growth rate per bet, and the rate at full and at double Kelly. A second mode takes an expected return and a volatility instead and returns the leverage. Kelly assumes your probability is exact, which is why overbetting it is how people go broke.

Calculator Type

Enter the price on offer and the probability you think is right. The gap between them is the edge, and the edge divided by the odds is the Kelly stake.

Odds Format

Odds *

Decimal odds include the stake. American odds may be negative. For fractional odds this is the top number.

Fractional Odds, Bottom Number

Only used when the format above is fractional.

Your Probability of Winning (%) *

Fraction of Kelly to Use (%)

100 is full Kelly. Half Kelly gives about three quarters of the growth with far smaller swings.

Bankroll ($)

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