Expected Value (EV) Sports Betting Calculator

What expected value means in sports betting

Expected value is the average net result of repeating the same wager many times under the same probability and price assumptions. A positive expected value bet has a price that pays more than its estimated chance warrants; a negative EV bet pays too little. EV describes a long-run average, not a prediction for the next game.

Your probability estimate is the key assumption. It can come from a model, a fair market price, or your own research, but the calculator does not verify that estimate.

Expected value formula for a wager

For a win-or-lose bet, EV equals the probability of winning multiplied by the profit if it wins, minus the probability of losing multiplied by the stake. At +110, a $100 winning bet earns $110 profit. If your estimated win probability is 50%, EV is 0.50 × $110 − 0.50 × $100 = $5.

A 5% expected return on stake means an estimated $5 long-run profit per $100 risked under those inputs. It does not mean each $100 wager is likely to win $5.

Use fair probabilities with care

A sportsbook’s implied probability includes margin. Comparing your estimate with a no-vig probability can help separate the market’s opinion from the bookmaker’s hold, but different markets and books can disagree. Recheck the odds near placement and record the source and time behind your estimate.