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Value Bet Calculator (EV)
A bet is only good if its expected value is positive. Check before you stake.
Expected value (EV)
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EV as % of stake
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Odds implied probability
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How to read the result
Odds hide a probability: 1 ÷ odds. Odds of 2.15 "think" the event has a 46.5% chance. If your serious estimate is 50%, that 3.5-point gap is your edge — and EV converts it to money: +$0.75 per $10 staked.
- Positive EV ≠ winning bet. You can lose this one: value only pays over volume (hundreds of bets).
- Negative EV = losing bet on average, even if it wins tonight. The bookmaker's margin (~5%) makes most gut-feel bets negative.
- The real judge is CLV: if your taken odds consistently beat closing odds, your estimates are good.
Your real EV, measured on your bets
Estimating EV before betting is good. Verifying afterwards that your estimates hold up (CLV, ROI per market) is what makes you improve. That's exactly what MyBankroll does.
Try MyBankroll free for 7 daysFAQ
What is a value bet?
A value bet is a bet whose odds are higher than the event's true probability justifies. Example: you estimate a 50% chance (fair odds = 2.00) and the book offers 2.15 — the bet has value. Betting only value spots is the only mathematically sound long-term strategy.
How is expected value (EV) calculated?
EV = (win probability × net profit) − (loss probability × stake). With $10 at 2.15 odds and an estimated 50%: EV = 0.50 × 11.50 − 0.50 × 10 = +$0.75, i.e. +7.5% of the stake. Positive EV doesn't guarantee the bet wins — it guarantees the bet is profitable on average, over volume.
Where does my "estimated probability" come from?
That's the hard part: a statistical model, closing odds from a sharper market, or rigorous personal analysis. Beware of optimism bias — systematically compare your estimates against actual results (that's exactly what CLV tracking in MyBankroll measures).
Go further
Informational tool. Positive EV rests entirely on the quality of your probability estimate — nothing is guaranteed. Gambling involves risk. Please bet responsibly. 18+/21+.