Kelly Criterion Calculator
Calculate the mathematically optimal bet size
Decimal Odds
Implied probability: 50.00%
Your Win Probability %
Your Bankroll
Example Scenarios
Kelly Recommendation
+10.00%
10.00%
$100.00
$50.00
$25.00
The Kelly Formula
b = odds - 1, p = win probability, q = 1 - p
Understanding Kelly Criterion
Find Your Edge
Estimate the true probability of winning. This requires research, analysis, and experience in your chosen sport or market.
Calculate Kelly
Enter the odds and your probability estimate. Kelly calculates what percentage of your bankroll to bet.
Choose Your Fraction
Full Kelly maximizes growth but has high variance. Half Kelly is recommended for smoother results.
Frequently Asked Questions
Free Kelly Criterion Calculator for Optimal Bet Sizing
Our Kelly Criterion calculator helps you determine the mathematically optimal bet size for any wager. Enter the odds and your estimated win probability to see exactly what percentage of your bankroll to bet.
The calculator shows Full Kelly, Half Kelly, and Quarter Kelly recommendations. Most professional bettors prefer Half Kelly for its balance of growth and risk management. The calculator instantly detects if you have positive expected value.
Kelly Criterion is proven to maximize long-term bankroll growth when used correctly. Our free calculator includes edge detection, multiple Kelly fractions, and works with any decimal odds. Essential for serious sports bettors.