Expected Value (EV) Calculator
Enter the odds you can bet at, your true win probability estimate, and your stake to see if a bet is +EV or -EV. Pair this with Closing Line Value (CLV) Explained to sharpen your probability estimates.
EV is calculated as (true win probability × profit if win) minus (loss probability × stake). Positive EV means the bet is profitable long-term at your estimated true probability; negative EV means the odds don't justify the bet.
What Is Expected Value (EV) in Betting
Expected value is the average amount you'd win or lose per bet if you could place the exact same wager thousands of times. A bet is +EV when your true win probability is higher than the sportsbook's implied probability — meaning the price doesn't reflect the real odds of the outcome. A bet is -EV when the opposite is true. Betting only +EV spots, consistently, is the entire foundation of long-term profitable betting.
How to Calculate EV
Formula: EV = (True Win % × Amount Won Per Bet) − (True Loss % × Stake).
Example: you bet $100 at -110 (implying 52.4%), but your true win probability is 55%. Winning returns $90.91 profit; losing costs your $100 stake. EV = (0.55 × $90.91) − (0.45 × $100) = $50.00 − $45.00 = +$5.00. That's a +5% EV bet — a real, sustainable edge if your 55% estimate is accurate.
Why +EV Betting Is the Only Long-Term Winning Strategy
Win rate alone is meaningless without context — you can win 60% of your bets and still lose money if you're consistently laying bad prices, and you can win only 45% of your bets and profit if your prices carry enough value. Betting is a game of finding mispriced lines, not just picking winners. The vig guarantees a loss for the average bettor over time, so the only way to beat the market long-term is to consistently find and bet +EV numbers.
EV at Different Odds & Edges
-110, 52.4% true probability: 0% EV — break-even, no edge.
-110, 55% true probability: roughly +5% EV per bet.
-110, 58% true probability: roughly +10.5% EV per bet.
+150, 40% true probability: 0% EV — break-even, no edge.
+150, 45% true probability: roughly +12.5% EV per bet.
Frequently Asked Questions
What does +EV mean in sports betting?
It means the bet has a positive expected return over the long run — your true win probability is higher than the price implies, giving you a mathematical edge.
How do I know my true win probability?
Through disciplined handicapping, tracked results, and comparing your numbers against closing lines over time. No single bet proves an edge — a large enough sample does.
Is EV the same as closing line value (CLV)?
They're related but not identical. EV is a projection based on your own probability estimate before the bet. CLV measures how your bet's price compares to the closing line after the market has absorbed all information — it's the best real-world proxy for whether your process is actually finding value.
Can a bet be +EV and still lose?
Yes, constantly. A single +EV bet can lose plenty of the time — EV describes your long-run average outcome across many similar bets, not the result of any one wager.
What EV percentage should I look for?
Any consistently positive EV is worth betting, but most sharp bettors target at least 2-5% EV per play after accounting for the vig, since smaller edges are harder to distinguish from normal variance and estimation error.