UnjuicedKelly Bet Sizing Calculator
Turn bankroll, price, and conviction into a disciplined fractional-Kelly stake.
Bankroll plan
Suggested position
Amount to wager
$295.45
Bankroll fraction
5.91%
Full Kelly
23.64%
Expected ROI
26.00%
Kelly is sensitive to your probability estimate. If the estimate is uncertain, use a smaller fraction or pass on the bet.
How to use the Kelly Bet Sizing
The Kelly criterion connects your estimated edge with bankroll size. Fractional Kelly reduces volatility by staking only part of the full recommendation.
- 1Enter your bankroll, offered odds, and projected win probability.
- 2Choose full, half, quarter, or another Kelly fraction.
- 3Use the suggested stake as a sizing reference, not a requirement.
Formula and assumptions
Kelly fraction = (decimal profit multiple × win probability - loss probability) / decimal profit multiple.
Kelly sizing assumes your probability estimate is accurate and your bankroll is dedicated to this strategy. Overconfidence can lead to oversized bets.
Kelly Sizing calculator FAQ
Answers about this free kelly bet sizing calculator, sports betting odds, payouts, and the math behind each result.
Why use fractional Kelly?
Fractional Kelly lowers stake size and bankroll volatility while preserving some of the method's growth-based logic.
What happens when there is no edge?
The Kelly recommendation is zero or negative, which indicates that the entered price does not justify a bet under your probability estimate.