Kelly Criterion Calculator
The gold standard of bankroll management. Use our 2026 Kelly Criterion tool to calculate the mathematically perfect stake to maximize growth and eliminate the risk of ruin.
📊 Kelly Criterion Calculator
👑 Recommended Optimal Stake
Staking **10.00%** of your bankroll maximizes compound growth while protecting against ruin (based on 2026 volatility models).
What is the Kelly Criterion?
Developed by John L. Kelly Jr. in 1956, the Kelly Criterion is a mathematical formula used to determine the optimal size of a series of bets. In sports betting, it is used to decide how much of your total money (bankroll) you should risk on a single bet given the odds and your estimated edge.
Unlike Fixed Stake betting (where you bet the same amount every time), the Kelly Criterion scales your bets proportionally to your confidence and the potential reward. This is how professional gamblers grow their wealth exponentially while keeping their risk of "going broke" at near zero.
The Mathematical Formula
The core Kelly formula is:
f* = (bp - q) / bWhere:
- f*: The fraction of your bankroll to bet.
- b: The decimal odds minus 1 (profit potential).
- p: The probability of winning.
- q: The probability of losing (1 - p).
Full Kelly vs. Fractional Kelly
While the "Full Kelly" provides the fastest growth, it can be extremely volatile. Many professional bettors use Half Kelly (0.5) or Quarter Kelly (0.25). This reduces the risk of massive swings in your bankroll while still maintaining a significant mathematical advantage over time.
By using a lower multiplier (Half or Quarter), you trade a bit of growth speed for a much "smoother" equity curve, which is often better for a bettor's psychology.
Why You Should Use This Tool
Most bettors lose because they over-bet their edge. If you have a 5% edge but bet 50% of your bankroll, you will eventually go broke due to variance. Our 2026 calculation engine ensures you stay within the "Safe Zone" of growth.
FAQ - Kelly Criterion
Does the Kelly Criterion work for casino games?
Yes, but only if you have a positive edge (like card counting in Blackjack or using specific bonuses). For games like Roulette or Slots where the house has the edge, Kelly will always recommend staknig $0.
When should I NOT use Kelly?
If you don't have a reliable way to estimate your win probability, the formula can be dangerous. Over-estimating your probability leads to over-betting, which is the fastest way to ruin.