Betting Tools
Expected Value (EV) Calculator
Find profitable bets by calculating the expected value of any wager. Enter your odds and true win probability to see if a bet has positive edge.
Calculate your betting edge
Your results update live as you adjust the odds, probability, or stake.
Enter American odds, such as +150 or -110.
How It Works
Convert Odds to Implied Probability
The sportsbook odds reveal what the market thinks the true probability is. For -110 odds, the implied probability is 52.38%.
Estimate the True Probability
Using your research, film study, or models, estimate what you believe the actual probability of the outcome is.
Calculate Expected Value
EV = (True Probability × Net Profit) − (Loss Probability × Stake)
Example: If you bet $100 at +150 odds and believe the true probability is 45%: EV = (0.45 × $150) − (0.55 × $100) = $67.50 − $55.00 = +$12.50
Interpret the Result
Positive EV means the bet is mathematically profitable over time. Negative EV means the sportsbook has the edge.
Quick Reference Table
| Odds | Implied Prob | Break-Even Prob | Your Edge at 55% | EV per $100 at 55% |
|---|---|---|---|---|
| -110 | 52.38% | 52.38% | +2.62% | +$4.55 |
| +100 | 50.00% | 50.00% | +5.00% | +$10.00 |
| +120 | 45.45% | 45.45% | +9.55% | +$21.00 |
| +150 | 40.00% | 40.00% | +15.00% | +$37.50 |
| -150 | 60.00% | 60.00% | -5.00% | -$8.33 |
| -200 | 66.67% | 66.67% | -11.67% | -$17.50 |
| +200 | 33.33% | 33.33% | +21.67% | +$65.00 |
| +300 | 25.00% | 25.00% | +30.00% | +$120.00 |
Expected value is calculated using a 55% true win probability and a $100 stake.
Expected Value Guide
Know Your Edge Before You Bet
What expected value really measures, how to work it out against a fair line, and how much edge it takes to beat the vig.
What Is Expected Value?
Expected value (EV) is the average amount you would win or lose per bet if you could place the same wager, at the same price, hundreds of times. It doesn’t predict the next result. It tells you whether the price is worth taking.
Every sportsbook price includes a built-in margin, called the vig or juice. That’s why most bets start out slightly negative. To come out ahead over time, you need prices where your real chance of winning is higher than the odds imply.
Example: A coin flip priced at -110 on both sides means you risk $110 to win $100. Win half the time and you average (0.50 × $100) − (0.50 × $110) = −$5 per bet. That $5 is the sportsbook’s cut.
Finding EV With a Fair Line
Illustrative numbers. This method assumes the sharp market’s no-vig price is close to the true probability.
How Much Edge Do You Need?
| Odds | Break-Even Win Rate | EV per $100 at +2 Points | EV per $100 at +5 Points |
|---|---|---|---|
| -200 | 66.67% | +$3.00 | +$7.50 |
| -150 | 60.00% | +$3.33 | +$8.33 |
| -110 | 52.38% | +$3.82 | +$9.55 |
| +100 | 50.00% | +$4.00 | +$10.00 |
| +150 | 40.00% | +$5.00 | +$12.50 |
| +200 | 33.33% | +$6.00 | +$15.00 |
“+2 points” means your true win probability is 2 percentage points above break-even (for example, 54.38% at -110). All figures use a $100 stake.
EV Rules & Tips
Your estimate is the weak link. At -110, a 52% estimate is worth about −$0.73 per $100, while 55% is worth +$4.55. Be conservative and track how your estimates hold up.
Use no-vig lines as a reality check. If your number is far from the sharp market’s fair price, double-check your work before you bet.
Positive EV still loses often. A bet with a true 55% win rate still loses 45% of the time. Results only even out over hundreds of bets.
Size small edges small. Pair EV with the Bankroll Manager. Most disciplined bettors risk 1–2% per bet or use fractional Kelly.
Shop the price. Getting +110 instead of -105 on the same side is worth about $7 per $100 in the example above. Odds boosts can add EV too, but read the terms first.
EV describes long-run averages, not guaranteed results. Only bet what you can afford to lose. Need help? Call or text 1-800-GAMBLER.
Frequently Asked Questions
Expected value (EV) is the average amount a bet is expected to win or lose over the long run. It combines the likelihood you assign to an outcome with the potential profit and the amount you could lose. A positive EV signals that the price is favorable based on your probability estimate.
A positive EV bet is one where your estimated true chance of winning is greater than the probability implied by the sportsbook’s odds. It does not mean the next wager will win; it means that repeatedly taking that price would be profitable in theory if your estimate is accurate.
Start with reliable data and a repeatable process. You might use your own model, injury and matchup analysis, performance data, market comparisons, or a projection source you trust. Be conservative: the quality of an EV calculation is only as strong as the true probability estimate behind it.
No. Individual bets are subject to variance, so a positive-EV bet can still lose. Expected value describes the long-term average across many similar opportunities, not a guaranteed result on a single wager. Always bet responsibly and use an amount appropriate for your bankroll.
EV tells you whether a price has theoretical value; the Kelly Criterion is a bankroll-sizing framework that uses your edge and the odds to suggest how much to risk. Many bettors use a fractional Kelly approach to reduce volatility because probability estimates are never perfect.
Ready to find value?
Calculate the expected value of your next bet.
Set your odds, true probability, and stake to see your potential edge in seconds.
