Expected Value Calculator
Enter odds and your estimated win probability to see if a bet has positive expected value.
What Is Expected Value in Sports Betting?
Expected value (EV) is the average amount you'd win or lose per bet if you placed the same wager thousands of times. A positive EV (+EV) bet means you expect to profit over time. A negative EV (-EV) bet means the sportsbook has the edge. Consistently finding +EV bets is the foundation of profitable sports betting.
How to Calculate Expected Value
The formula is: EV = (Win Prob × Profit if Win) - (Loss Prob × Stake). You need two inputs: the odds offered by the sportsbook and your honest estimate of the true probability that the bet wins.
For example, a bet at +150 odds with a 45% true win probability: profit if win = $150 on a $100 bet, so EV = (0.45 × $150) - (0.55 × $100) = $67.50 - $55.00 = +$12.50 per $100 wagered. That's a +EV bet.
How to Estimate True Probability
This is the hard part, and it's where your edge comes from. Some approaches: compare odds across multiple sportsbooks to find the sharpest line, use statistical models built on historical data, follow line movement to gauge where sharp money is landing, or develop deep knowledge of specific sports, teams, or prop markets where books may be less efficient.
The "Edge vs. Book" metric shown above compares your estimated probability to the book's implied probability. A positive edge means you think the event is more likely than the odds suggest — that's where value lives.
Why EV Matters More Than Win Rate
You can have a 40% win rate and still be profitable if you're consistently betting at +EV. A bettor who wins 40% of bets at +200 odds is making money because the payouts on wins more than cover the losses. Conversely, winning 60% of bets at -200 odds barely breaks even after vig. EV captures the full picture that win rate alone misses.