Kelly Calculator
Expected Value
7.38%
Fraction of Bankroll to Wager
3.49%
Amount to Wager with $5,000 bankroll
$174.38
Kelly Coefficient should be between 0-1. Use lower values (0.1-0.5) for conservative betting.
Only bet when Expected Value is positive and you have an edge over the bookmaker.
Determine optimal bet size to grow your bankroll efficiently
The Kelly Criterion calculator helps you calculate the optimal percentage of your bankroll to wager on a given bet. It uses your current bankroll size, the odds being offered, and your estimated fair probability of the outcome to determine the ideal stake. By betting the optimal amount, you maximize long-term growth while minimizing the risk of going broke.
For example, if you believe the fair win probability for a team is 50%, but the sportsbook is offering +110 odds, the Kelly formula will recommend how much of your bankroll you should risk based on this edge. As a rule, you should only use this tool when you believe you have found a bet with positive expected value.
Tip: You can estimate fair win probability using sharp sportsbook markets and no-vig calculators.
Frequently Asked Questions
The Kelly Criterion is a formula used to calculate the optimal bet size for maximizing long-term bankroll growth while minimizing risk of ruin. It considers both the edge you have and your current bankroll.
The Kelly Criterion helps you avoid betting too much on any single wager while maximizing the compounding effect of your edge. It provides a mathematically sound approach to bet sizing based on your perceived advantage.
You need to enter the odds being offered by the sportsbook, your estimate of the fair win probability, and your current bankroll size. The calculator will then tell you the optimal amount to wager.
You can estimate fair win probability by removing the vig from sharp sportsbooks using a no-vig calculator or by using trusted models and projections that reflect true win probabilities.
No system can eliminate risk. The Kelly Criterion helps manage risk by avoiding oversized bets but still requires accurate estimation of your edge. Overestimating your edge can lead to poor outcomes, so always be conservative with your probability estimates.
Yes. Many bettors prefer to use a half Kelly or quarter Kelly approach to further reduce variance and protect their bankroll from estimation errors in the edge calculation.