Kelly Criterion Calculator
The Kelly Criterion answers a narrower question than EV: not whether to bet, but how much of your bankroll to risk, to maximize long-run bankroll growth given your estimated edge.
How it works
b is net decimal odds (odds - 1), p is your estimated win probability, q is 1 - p. f* is the fraction of your bankroll to stake. Many bettors use half-Kelly (f*/2) to reduce variance at the cost of slower growth.
Worked example: Odds 2.10 (b = 1.10), p = 0.54: f* = (1.10 x 0.54 - 0.46) / 1.10 ~= 12.5% of bankroll. Half-Kelly ~= 6.3%.
FAQ
Why would I ever use half-Kelly instead of full Kelly?
Full Kelly is mathematically optimal for growth but has large short-term swings if your probability estimate is even slightly off. Half-Kelly trades some growth for meaningfully lower variance.
What if my edge is negative?
Kelly correctly returns 0% - the formula never recommends staking on a bet you believe has negative expected value.
Related tools
18+. These tools are analytical only - they do not accept bets, do not predict outcomes, and do not guarantee profit. Gamble responsibly. Sports betting regulations vary by jurisdiction; you are responsible for understanding and complying with the laws where you live.
Canonical URL: https://aipredicts.bet/tools/kelly-criterion-calculator