Kelly criterion calculator
The mathematically optimal bet size from your edge and bankroll - with fractional Kelly options, because full Kelly is a wild ride.
Inputs
American oddsWhat the Kelly criterion does
Kelly sizing maximizes the long-run growth rate of your bankroll. The formula is f* = (bp - q) / b, where b is the decimal odds minus one, p is your true win probability, and q = 1 - p. It stakes more when your edge is bigger or the price is better, and exactly zero when you have no edge.
Why fractional Kelly
Full Kelly assumes your probability estimate is exactly right. It never is. Overestimating your edge with full Kelly overbets badly, and the drawdowns are brutal - half or quarter Kelly keeps most of the growth with a fraction of the variance, which is why nearly every serious bettor sizes fractionally. Our own tracked board counts picks at a flat 1 unit for transparency, but quarter-Kelly on the same edges is a sensible private sizing rule.
Garbage in, garbage out
Kelly is only as good as the probability you feed it. A market-implied fair probability - like the consensus numbers on the EV board - is a far more reliable input than gut feel.
Daily Results
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The daily pick and its graded receipt, straight from the tracked board.
For analytics and education only. Lines move quickly; verify prices before making any paid decision.