Kelly Calculator
Calculate the optimal bet size using the Kelly Criterion. Enter the odds and your estimated win probability to determine what fraction of your bankroll to wager.
Expected Value
26.00%
Fraction of Bankroll to Wager
11.82%
Amount to Wager with ${{ bankroll }} bankroll
$1182
Kelly Criterion calculates the optimal fraction of your bankroll to wager to maximize long-term growth. The multiplier (typically 0.25) reduces the Kelly fraction to minimize risk while still capturing most of the growth benefit.
Frequently Asked Questions
What is the Kelly Criterion?
A formula that calculates the optimal fraction of your bankroll to stake on a positive-EV bet to maximise long-term growth while controlling risk.
What Kelly multiplier should I use?
Many bettors use a fractional Kelly (0.25 to 0.5) rather than full Kelly to reduce variance and the impact of errors in their win-probability estimate.
How is the Kelly stake calculated?
Kelly fraction = (b × d − q) / b, where b is decimal odds minus 1, d is your win probability and q is 1 − d. Multiply the result by your bankroll and any fractional multiplier to get the stake.
Why not always bet full Kelly?
Full Kelly assumes your win probability is exact. If it is slightly off, full Kelly over-bets and raises the risk of large drawdowns, so fractional Kelly is the safer default.
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