Enter your stake, bookmaker odds, and true win probability to find out if a bet has positive expected value (+EV). The Expected Value (EV) Calculator computes your expected value, expected ROI, and probability advantage — showing whether the sportsbook has underpriced the true chance of winning.
Expected Value (EV)
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Expected ROI
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Probability Advantage
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Implied Probability (Book)
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Potential Profit (if win)
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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 over. A positive EV (+EV) means the bet is profitable in the long run, while a negative EV (-EV) means the sportsbook has the edge. EV is calculated as: (True Win Probability × Potential Profit) − (True Loss Probability × Stake).
The formula is: EV = (P_win × Profit) − (P_loss × Stake), where P_win is your estimated true probability of winning and Profit is what you'd collect minus your stake. For example, a $100 bet at +110 American odds with a 55% true win probability gives: EV = (0.55 × $110) − (0.45 × $100) = $60.50 − $45.00 = +$15.50.
Implied probability is derived from the sportsbook's posted odds and includes their built-in margin (the vig or juice). True probability is your own estimate of the real chance an outcome occurs — typically sourced from sharp no-vig odds, a sports betting model, or closing line value. A bet has positive EV when your true probability exceeds the book's implied probability.
A bet is +EV when the Expected Value result shown by the calculator is greater than $0. This means your estimated true probability of winning is higher than the sportsbook's implied probability — i.e., the book has underpriced the real chance of the outcome occurring. The larger the positive EV, the more attractive the bet.
Use an EV calculator before placing any wager to determine whether you're getting fair value or better. It's especially useful when line shopping across sportsbooks, comparing your model's probability to posted odds, or evaluating whether a promoted odds boost is genuinely valuable. Consistently betting +EV lines is the foundation of profitable sports betting.
No. EV is a long-run average projection, not a guarantee for any single bet. You can have a +EV bet and still lose it — that's normal variance. Over hundreds or thousands of bets, consistently betting +EV opportunities should yield profits, but short-term results can vary significantly due to luck.
The most common method is to use the no-vig (fair) odds from a sharp sportsbook (like Pinnacle) and convert those to a probability by removing the vig. You can also use a proprietary sports betting model or statistical data. The more accurate your true probability estimate, the more reliable your EV calculation.
Yes. This calculator supports American (moneyline), decimal, and fractional odds formats. Simply select your preferred format and enter the bookmaker's odds accordingly. The underlying EV math is the same regardless of the format — the calculator converts to a common scale before computing your edge.