Positive EV betting: how to find and calculate +EV bets

A positive EV bet (+EV, plus EV) is a bet where the odds pay more than the real probability of the outcome is worth, so it makes money on average over many bets.

RebelBetting is EV betting software that finds +EV bets across sportsbooks in real time.

How positive EV betting works with RebelBetting

• RebelBetting removes the vig from sharp lines to get the fair odds.
• Sportsbook odds better than the fair odds are +EV.
• You bet a share of your bankroll that matches the edge.
• Over a thousand bets or more, the edge shows in your results.

1. Turn the odds into a probability

For plus odds: 100 ÷ (odds + 100). +150 implies 100 ÷ 250 = 40%. For minus odds: odds ÷ (odds + 100), without the minus sign. −110 implies 110 ÷ 210 = 52.4%.

2. Remove the vig to get the fair odds

A line of −110 on both sides adds up to 104.8%. The extra 4.8% is the overround, the sportsbook's built-in margin (the vig). Take it out and each side has a 50% chance: fair odds of +100. This no-vig line from a sharp sportsbook is your best estimate of the real probability.

3. Calculate the expected value

EV = (real probability × profit if you win) − (probability of losing × stake). If another sportsbook offers +110 on a side that's fair at +100, a $100 bet gives (0.5 × $110) − (0.5 × $100) = +$5. That's +5% expected value.

The same side at −110 gives (0.5 × $90.91) − (0.5 × $100) = −$4.55. You need to win 52.4% of the time at −110 just to break even.

Positive EV, +EV and plus EV mean the same thing. It's about the price, not about how likely the bet is to win: an underdog at +300 can be +EV, and a favorite at −250 can be −EV.

• Compare with a sharp line. Sharp sportsbooks move their lines when professional money comes in, so their no-vig odds are the closest thing to the real probability.
• Shop many sportsbooks. Soft books set lines for recreational bettors and update them later. The more books you can bet at, the more +EV bets you'll find. Player props and smaller leagues move less money, so soft lines there drift further from the sharp price.
• Act before the line moves. Soft lines catch up with the sharp ones, sometimes within minutes.
• Check the closing line. If you keep getting better odds than the sharp line at kickoff, your bets have value. Read more about closing line value.

Doing these steps by hand for every game and every sportsbook takes longer than the edge lasts. RebelBetting does it in real time: it removes the vig from sharp lines, compares them with the sportsbooks it covers, and shows each +EV bet with a suggested stake. See how EV betting with RebelBetting works.

The Kelly criterion sets your stake from the edge and the odds: (b × p − q) ÷ b, where b is the profit per $1 staked, p the real probability of winning and q the probability of losing. At +110 with a real 50% chance: (1.10 × 0.5 − 0.5) ÷ 1.10 = 4.5% of your bankroll.

Full Kelly swings hard, and an overestimated edge makes it worse. Most bettors use a fraction: half Kelly (2.3% here) or quarter Kelly (1.1%). Read more about the Kelly criterion.

Even good bets lose, sometimes many in a row. That's variance. Bet only money you can afford to lose, and judge your results over a thousand bets or more.

• Confusing +EV with likely to win. Expected value is about the price. Many +EV bets are underdogs that lose more often than they win.
• Judging too early. A losing week tells you very little. It takes a couple of thousand bets before results show your edge reliably.
• Skipping bets you don't like. Picking only the +EV bets that feel right changes your results. Read about selection bias.
• Chasing losses. Raising your stakes after a losing run adds risk without adding edge.