Kelly Criterion
Definition
A formula for determining the optimal bet size based on your edge and bankroll. It maximizes long-term growth while minimizing risk of ruin. Formula: (bp - q) / b, where b = decimal odds - 1, p = probability of winning, q = probability of losing.
Example
With a 5% edge at 2.00 odds, Kelly suggests betting 5% of your bankroll.
Related terms
Expected Value (EV)
The average amount you can expect to win or lose per bet if you were to place the same bet many times. Calculated as: (Probability of Winning × Potential Profit) - (Probability of Losing × Stake). A positive EV (+EV) indicates a profitable bet over time.
+EV (Positive Expected Value)
A bet where the expected value is greater than zero, meaning the true probability of winning is higher than what the odds imply. These are the opportunities EVSignals identifies.
-EV (Negative Expected Value)
A bet where the expected value is less than zero. Most bets offered by sportsbooks are -EV due to the built-in margin (vig/juice).
Edge
The percentage advantage you have over the sportsbook. Synonymous with +EV percentage. An edge is created when you can identify the true probability more accurately than the market.
Use EVSignals to find +EV opportunities
Scan Kalshi, Polymarket, and 500+ sources for positive expected value edges.