Value bet calculator
Calculate Expected Value (EV) for any bet
Calculate Expected Value (EV) — the mathematical edge — for any betting opportunity.
What is Expected Value?
Expected Value (EV) is the average amount you'd win per bet if you placed the same bet thousands of times. Positive EV means you'd profit in the long run; negative EV means you'd lose. Every professional bettor lives and dies by EV — picking winners is irrelevant if you're paying too much for them.
The formula is simple: EV = (probability of winning × profit if won) − (probability of losing × stake). If the bookmaker offers odds that imply a lower probability than your true estimate, the bet has positive EV. If they imply a higher probability, it has negative EV (and you should skip it). Once you've identified positive EV, the Kelly criterion tells you how much to stake. You can also cross-check market odds against fair no-vig odds to verify your edge.
See also: Kelly criterion, No-vig (fair odds), Closing Line Value
How to use this calculator
- 1Enter the bookmaker's decimal odds.
- 2Enter your estimated true probability (the hardest part — be honest).
- 3Enter your intended stake.
- 4See EV in money, EV as a percentage, and the breakeven probability — the minimum probability needed to make the bet +EV.
Example: finding value on a tennis match
Bookmaker offers Player A at 2.50. The implied probability is 40% (1/2.50). You've watched both players' recent matches and estimate Player A's true probability of winning is 47%. EV per €100 stake = (0.47 × €150) − (0.53 × €100) = €70.50 − €53 = +€17.50. That's a 17.5% edge — extremely strong value. Place the bet.
The honest probability test
EV calculations only work if your probability estimate is honest. If you mentally adjust the probability to make a bet look like value (because you really want to bet), you're fooling yourself. Pro bettors test their estimates by tracking thousands of bets and seeing if their forecasted edge matches actual ROI.
When to use
- Before placing any bet — make EV checking a habit
- When filtering tipster picks — only follow positive-EV ones
- To track your edge over time — compare predicted EV to actual results
- To decide between two bets — always take the higher EV%
Frequently asked questions
What is the Value bet finder calculator?
Expected Value (EV) is the average amount you'd win per bet if you placed the same bet thousands of times. Positive EV means you'd profit in the long run; negative EV means you'd lose.
How does the Value bet finder calculator work in practice?
Bookmaker offers Player A at 2.50. The implied probability is 40% (1/2.50). You've watched both players' recent matches and estimate Player A's true probability of winning is 47%. EV per €100 stake = (0.47 × €150) − (0.53 × €100) = €70.50 − €53 = +€17.50. That's a 17.5% edge — extremely strong value. Place the bet.
What is the most common mistake with the Value bet finder calculator?
EV calculations only work if your probability estimate is honest. If you mentally adjust the probability to make a bet look like value (because you really want to bet), you're fooling yourself. Pro bettors test their estimates by tracking thousands of bets and seeing if their forecasted edge matches actual ROI.
When should I use the Value bet finder calculator?
Before placing any bet — make EV checking a habit. When filtering tipster picks — only follow positive-EV ones. To track your edge over time — compare predicted EV to actual results.