What this does: Enter your odds, your estimated win probability, and your bankroll. This calculator returns the Kelly-optimal stake and the safer half-Kelly.
Key takeaways
- Kelly sizes bets to maximize long-term bankroll growth.
- It only recommends a bet when you have an edge.
- Most sharp bettors use half-Kelly to reduce variance.
Kelly criterion calculator
How it works
Kelly uses your net odds and win probability to compute the fraction of bankroll that maximizes long-term growth: f = (b x p minus (1 minus p)) / b, where b is the net decimal odds. If the edge is zero or negative, Kelly recommends no bet. Half-Kelly stakes half that fraction to cut variance.
Why this matters
Bet sizing protects the edge that reduced juice and +EV betting create. See expected value and sharp sportsbooks.
FAQ
What is the Kelly criterion?
A formula that sizes each bet as a fraction of bankroll to maximize long-term growth, based on your edge.
Why use half-Kelly?
Full Kelly is volatile and assumes your probability is exact. Half-Kelly keeps most of the growth with far less swing.
What if Kelly says zero?
It means the inputs imply no edge, so the model recommends not betting.
Related guides
Related guides
Expected Value Betting · Low Vig / Reduced Juice · Betting Calculators
About Bet105
Bet105 is a reduced-juice (-103/-105) sportsbook for sharp and crypto bettors. It welcomes winning players rather than limiting them, and crypto payouts clear fast with no KYC for standard play.