Expected Value (EV)
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Expected Value (EV) is the average amount you can expect to win or lose per bet if you placed the same wager many times. A positive EV (+EV) bet means you have a mathematical edge over the sportsbook, while a negative EV (-EV) bet means the house has the advantage. It\'s calculated by multiplying each possible outcome by its probability and summing the results. EV is the single most important concept in profitable sports betting because it separates long-term winners from recreational bettors who rely on gut feelings. Professional bettors treat every wager as an investment decision, only placing bets when the expected value is in their favor.
Example
You find a bet at +150 odds that you estimate has a 45% chance of winning. EV = (0.45 x $150) - (0.55 x $100) = $67.50 - $55 = +$12.50. This is a +EV bet because you expect to profit $12.50 per $100 wagered over time. Here\'s another example: a -200 favorite with a 60% win probability. EV = (0.60 x $100) - (0.40 x $200) = $60 - $80 = -$20. Despite the team being likely to win, this is a -EV bet because the odds don\'t offer enough payout relative to the risk. The key insight is that winning percentage alone doesn\'t determine profitability—the relationship between odds and true probability does.
Common Questions
What is a good expected value for a bet?
What is a good expected value for a bet?
Any positive expected value is good, but most sharp bettors look for at least +2% to +5% EV to account for variance and potential errors in probability estimates. Higher EV bets are rarer but more valuable. Bets with +1% EV or less may not be worth the effort once you factor in the uncertainty of your probability model. As a general rule, the more confident you are in your probability estimate, the lower the EV threshold you can accept.
Can you lose money on +EV bets?
Can you lose money on +EV bets?
Yes, absolutely. EV is about long-term expectation, not individual outcomes. You can lose many +EV bets in a row due to variance—this is completely normal and expected. A +5% EV bettor might still have losing weeks or even losing months. The math only works out over hundreds or thousands of bets, which is why bankroll management and proper unit sizing are essential to surviving the inevitable downswings while maintaining your edge.
How do I find +EV bets?
How do I find +EV bets?
Compare sportsbook odds to sharp market prices (like Pinnacle) or use tools like +EV Bets that calculate fair odds for you. When a book offers better odds than the fair price, that's +EV. You can also build your own probability models for specific sports or markets. Line shopping across multiple sportsbooks is critical because pricing inefficiencies between books are one of the most reliable sources of +EV opportunities for everyday bettors.
What is the difference between EV and ROI?
What is the difference between EV and ROI?
Expected value measures the projected profit or loss on a single bet, while ROI (Return on Investment) measures your actual profit as a percentage of total money wagered over time. A bettor consistently placing +EV bets should see a positive ROI over a large enough sample. Think of EV as the theoretical prediction and ROI as the real-world result. They should converge over thousands of bets, but short-term ROI can vary wildly due to variance.