Kelly Criterion
Determines optimal stake size to maximise long-run bankroll growth based on your edge and odds.
How it works
Inputs
- Win probability
- Decimal odds
- Bankroll
- Kelly fraction (%)
Results
- Full Kelly %
- Fractional Kelly stake
- Edge analysis
- Fraction comparison
When to use
Use after finding a +EV bet to determine how much of your bankroll to wager.
Example
55% win probability at 2.00 odds with $1,000 bankroll — half Kelly suggests $50 stake.
Frequently Asked Questions
What is the Kelly Criterion?
The Kelly Criterion is a formula that calculates the optimal percentage of your bankroll to wager on a bet, based on your edge and the odds offered. It maximises long-term growth while avoiding ruin.
Should I use full Kelly or fractional Kelly?
Most bettors use fractional Kelly (25-50% of the full Kelly amount). Full Kelly is mathematically optimal but assumes your edge estimates are perfectly accurate, which they rarely are. Fractional Kelly reduces variance.
Need live odds data?
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