Kelly Criterion Calculator
Calculate optimal bet sizing with the Kelly Criterion. Maximize your bankroll growth long-term.
Your parameters
The Kelly Criterion
The Kelly Criterion is a mathematical formula that determines the optimal bet size to maximize your bankroll growth long-term.
The formula
Kelly % = (p × b - q) / b
Where:
- p = probability of winning
- q = probability of losing (1 - p)
- b = net odds (decimal odds - 1)
Why use Half Kelly?
Full Kelly is mathematically optimal but very aggressive. Variance is high and a few bad results can seriously dent your bankroll. Most professional bettors use Half Kelly (50%) or Quarter Kelly (25%) to reduce variance while maintaining solid growth.
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