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| Expected Value | |
| Expected Value |
What is EV Calculator?
The Expected Value (EV) is a measure used in gambling and finance to calculate the average outcome of a given bet (or investment) over the long run. EV looks at all possible outcomes and their probabilities to tell you if a wager is, theoretically, profitable (positive EV) or not (negative EV).
In sports betting, EV helps you compare your estimate of a team’s chance of winning versus the implied probability from the betting odds. If your estimated chance of winning is higher than what the odds imply, you have a positive EV bet.
How to Use the EV Calculator
1. Select your Odds Type (American or Decimal).
2. Enter the odds in the “Odds” field.
3. Enter your estimated chance of winning (e.g., 50%) in the “Win Percentage” field.
4. Optionally, enter a Wager Amount to see the EV in dollars. If left blank, the calculator will skip dollar EV.
5. Click “Calculate EV” to view both the percentage EV and the dollar EV (if wager was entered).
Example
Suppose you find a team at +150 American odds, and you believe they have a 45% chance of winning. By entering +150 and 45%:
- Decimal multiplier is 1.50 on the winnings.
- EV = (1.5 × 0.45) – (1 – 0.45) = 0.675 – 0.55 = +0.125 (12.5%).
If you bet $100 (optional), your expected profit is $12.50 on average for this wager.
Frequently asked questions
What is expected value in betting?
Expected value is the average profit or loss per bet if the same bet were repeated many times: win probability times profit, minus loss probability times stake. A positive-EV bet makes money over volume even though any single result is random.
Where does my win probability estimate come from?
Common sources are your own model, no-vig consensus prices from sharp books, or closing lines. The EV number is only as good as this input — garbage probability in, garbage EV out.
I bet positive EV but keep losing. Is the math wrong?
Not necessarily — variance dominates small samples. A 55% edge still loses 45% of the time, and losing streaks of five or more are routine. EV betting is judged over hundreds of bets, with closing line value as the earlier signal.
What is the difference between EV and ROI?
EV is the theoretical average profit per bet before you place it; ROI is the realized return over bets you have already settled. With enough volume ROI converges toward your average EV.