Expected Value (EV) Calculator
Expected Value (EV) reveals whether a bet is mathematically profitable over time. Enter your probability estimate and odds to see if you've found genuine value.
What is Expected Value?
Expected Value (EV) tells you how much you can expect to win or lose on average per bet. Professional bettors only place bets with positive EV (+EV).
Positive EV Example
If you find odds of 2.50 on an outcome you believe has a 45% chance of happening:
- Win: 45% × (2.50 × 100 - 100) = 45% × 150 = +67.50
- Lose: 55% × (-100) = -55.00
- EV = +12.50 per 100 staked
Why EV Matters
Even with +EV bets, you'll lose individual bets. But over hundreds of bets, positive EV accumulates into profit. This is how professional bettors and bookmakers operate.
Understanding Expected Value in Betting
Expected Value is the most important concept in gambling mathematics. It tells you how much you can expect to win or lose per bet over the long run. Positive EV bets make money over time. Negative EV bets lose money over time. Every casino game has negative EV for players, that is how casinos profit.
How EV is Calculated
EV equals the probability of winning multiplied by the win amount, minus the probability of losing multiplied by the loss amount. For a coin flip at even money: (0.50 times 1) minus (0.50 times 1) equals 0. Fair game, zero EV. If the same flip paid 2.10, EV becomes positive 5 percent.
Finding Positive EV in Sports Betting
Unlike casino games, sports betting occasionally offers positive EV opportunities. When your assessed probability of an outcome exceeds the implied probability of the odds, you have found value. The challenge is accurately assessing true probabilities.
Why Most Bettors Have Negative EV
Bookmaker margins ensure that betting randomly produces negative EV. Even if you pick winners at the implied probability rate, margins eat your bankroll over time. Consistent positive EV requires genuine predictive edge.