Download the appBy Outlier · Updated
About the Expected Value Calculator
Expected value (EV) is the average profit or loss you could expect from the same bet over many tries. This calculator uses the odds, your stake, and your estimate of the chance of winning.
How to use this calculator
- Choose an odds format and enter the sportsbook odds.
- Enter your stake: the amount you plan to bet.
- Enter your estimated win chance, or switch to fair odds.
- Check the expected profit. Use the table to see how a lower or higher win estimate changes it.
Formula and definitions
- Expected profit = stake × (p × d − 1).
- Expected return on stake = p × d − 1. Multiply by 100 to show it as a percentage.
- Break-even win chance = 1 ÷ d.
- Probability edge = your win estimate − break-even win chance.
- p
- Your estimated win chance as a decimal. A 50% chance is 0.50.
- d
- The offered odds in decimal format. +110 is 2.10.
- Break-even
- The point where average winnings cover average losses.
- Probability edge
- The gap between your estimate and the break-even chance, measured in percentage points.
Worked example
- Bet $100 at +110 with an estimated 50% chance of winning.
- A win earns $110 profit. A loss costs $100.
- Expected profit = (0.50 × $110) − (0.50 × $100) = $5.
- That is 5% of the stake. The break-even win chance is 47.62%.
How to read your result
Positive EV means the bet could earn a profit on average if your win estimate is correct. Negative EV means it could lose money on average.
Probability edge and return on stake measure different things. A gap of 5 percentage points in win chance does not mean a 5% return.
Assumptions and limitations
- Your win chance is an estimate. A personal model or an estimate from market odds can be wrong.
- The bet has only two results: win or loss. Pushes, fees, taxes, and changing odds are not included.
- The profit shown for 100 identical bets is an average. Actual short-term results can be very different.
Common mistake to avoid
The win chance implied by the offered odds is the break-even point. Using that same chance as your estimate gives zero EV before costs.
Put your result to work
Try a related calculator, or read our sports betting strategy guides to learn more.
- No-Vig Fair Odds Calculator — Odds without sportsbook margin
- Kelly Criterion Calculator — Stake sizing
- Implied Probability Calculator — Break-even win chance
Expected Value FAQs
What does a +5% EV bet mean?
If your win estimate is correct, the bet earns an average of $5 per $100 staked over many tries. Any single bet can still lose the full stake.
How do I estimate fair win probability?
You can start with a model tested against past results, or market odds with the sportsbook margin removed. Both can be wrong. Try lower and higher estimates to see how much your result changes.
How results are calculated
Results use the formulas and assumptions above. Money is rounded to cents. Odds and percentages are rounded to make them easier to read.
The calculator uses the odds and win chances you enter. It does not load live odds.