The odds of a coin flip are 50/50. The true odds of wagering on heads or tails are written as even money (+100). Most sporting event outcomes are also 50/50, although there are ties in soccer and sometimes even in the NFL. But oddsmakers don't put +100 on each side of a game, or they wouldn't be able to take a cut after paying out the winners. That's why they make it -110, -115, or -120, forcing a bettor to lay $115 -115 on a game to win $100. Theoretically, betting on tails would have a positive expected value if they made a coin flip -115 on heads and +115 on tails. A sports bettor would expect to win with tails 50% of the time, but is getting plus money (+115).
The calculation works like this:
Expected Value = (Probability of Winning, 50% or 0.5) x (Amount Won) minus (Probability of Losing, 50% or 0.5) x (Amount Lost)
EV = 0.5 x $115 - 0.5 x $100
EV = $57.50 - $50
Expected Value = $7.50
The expected value of this bet is $7.50. Therefore, this would be a 7.5% positive expected value opportunity, as $7.50 is 7.5% of your $100 wager. One of the best ways to consistently beat the closing line is to find positive expected value bets.
Here are a few different ways of finding positive EV bets including using EV betting tools.
Sports Betting Projections-Based Model
Projections-based modeling is one route that helps find +EV bets and it can help you too. For instance, ESPN broadcasts projections of expected winners on marquee sports events all the time. They use computer modeling based on three years of player stats and team production, emphasizing recent performance. ESPN's computer model gave the Eagles a 56.1 percent chance of defeating the Chiefs in the 2025 Super Bowl. That turned out to be correct as Philadelphia won, 40-22. The Eagles opened at +110 on the moneyline and closed at +104 as more money came in on the underdog to win the game. Bettors agreeing with their model grabbed more positive value at +110 before the line moved to +104. The good thing about models is that one can use hard data or tinker with specific stats based on what adjustments a bettor thinks need to be made. That introduces personal bias, but oddsmakers do that when making certain lines, such as giving an edge to public teams or overreacting to a team after a surprising blowout win or loss in the previous week. Other models place a heavier emphasis on home play and recent head-to-head matchups.
Market-Based Model
Another way to gauge positive expected line value is by letting the betting market decide. Market-based models aren't interested in statistical matchups but revolve around the notion that line movement best reflects what teams the betting sharps are on.
It's similar to the stock market and day traders.
For instance, if a football or basketball total moves 2 or 3 points, that's a sign that a string of respected bettors have pounced on a weak number. Sharp bettors would quickly search for books that have yet to adjust their totals. Any book offering the direction the sharp bettor wants (OVER or UNDER) at greater than even-money odds (+105, +110) would be a positive EV bet. These sharp bettors aren't interested in statistical game analysis but react to betting market indicators.
Arbitrage Betting
Another form of positive EV wagering is Arbitrage Betting, also called "Arbing" or "Sure Betting". Instead of putting the odds in your favor to win one wager, you're locking in both sides of the same game with two bets to guarantee a small profit. Sportsbooks will have different odds with lines shifting during the day and the week. For instance, if one sportsbook is offering odds of +120 on the NY Giants to win on the moneyline against Dallas, and the Cowboys are at minus-105 at another book, you could wager $200 on the Giants (+120) to win $240, and $225.50 on the Cowboys to win $214.76. You're guaranteed to win one bet and lose the other, locking in a profit of almost $15 and increasing your bankroll. The outcome of the game doesn't matter.
Pro tip for this approach: The more books you can visit or play online, the greater your chances of finding the right moneyline differential to lock in a positive EV bet.
Value Betting
The odds of winning games like blackjack, craps, and slot machines can be numerically calculated. Casinos know those figures and compute payouts. By law, all video lottery games must return between 87% and 95%, while a blackjack table hold percentage is around 15%.
Sports betting is different.
Oddsmakers make relatively good numbers to carve out a profit margin in betting markets. But sporting events introduce variables that are not as quantifiable as dice rolls or coin tosses. Emotion, road travel, injuries, and situations on the field and the court can impact the outcome. Making your own numbers and comparing them to the opening odds can help identify value in betting with your bets.
Follow the Money, Honey
Line shopping is essential to finding positive EV betting. Odds and betting lines are constantly shifting, so it helps to have multiple sportsbooks. And not all books have the same kind of customer base. Some books take much more action, some cater to casual bettors, while others have a higher percentage of big bettors. When a big player makes a move, a book pays attention and often moves a number out of respect for the sharp action. By contrast, if casual bettors are all over a public team on a marquee TV game, they'll be less inclined to move the number, knowing that the public is usually wrong.
Staying Positive
Positive EV (+EV) betting is a wager with a price lower than the "true odds" calculation. Consistently winning at sports betting is about putting the closing odds in your favor. There are several methods to utilize, such as a sports betting projections-based model, a market-based model, arbing, and value betting. None guarantees a win on every game, but they incrementally increase the percentages in your favor. Bookies make their profit on casual bettors who lose regularly—that doesn’t have to be you. Use these tips to start betting better, or grab my free premium picks to help you win more.
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