The OddsJam Positive EV (+EV) tool helps you find bets that are mispriced (positive expected value) in the market, in your favor. When a bet is positive expected value, that means market odds indicate that the true probability of this bet is more favorable than what the specific listed sportsbook predicts.

This doesn’t necessarily mean any specific bet is going to win. Rather, because this bet is mispriced, you’re taking slightly less risk for a higher payout than you would otherwise get.

For a quick practical example, imagine 10 sportsbooks had -110 odds for a specific bet. However, the 11th sportsbook had +110 odds for that same bet. According to the market, that 11th sportsbook has PROBABLY mispriced their bet in your favor, making the bet positive expected value.

Don't feel like reading an article? Watch Alex, cofounder of OddsJam, walk through the concept of +EV and the OddsJam tools!

The unfortunate part of sports betting is that when a sportsbook deems a bet a 50/50 bet, the odds will be priced at -110 on each side. This is the vig that sportsbooks charge. So, using a coin flip example, both sides would be priced at -110 odds, which has an implied probability of 52.38% each for heads and tails.

Let's say you flipped the coin 100 times and bet $100 on heads every time at -110 odds (meaning a $100 bet wins $90). Statistically speaking, the results would be heads 50 times and tails 50 times. However, because the provided odds are worse than 50/50, over time you will lose money. For every time it was heads you would have profited a total of $4,500 (50 * $90), and for the 50 times it was tails you would have lost a total of $5,000 (50 * 100) leaving you with a net loss of $500.

What we have learned is that just because it might land on heads one individual time, you know that in the long run you would not be able to profit with this strategy. This is an example of a negative expected value bet.

Now let’s instead say we discovered that we are using a weighted coin, and that heads actually has a 60% chance and only 40% for tails. In this case, for 100 coin flips we would profit a total of $5400 on heads (60 * $90) and only lose $4000 on tails (40 * $100), profiting $1400. Again, just because one flip of the coin might land on tails, you would know that over time you will make money with this strategy. This is what positive expected value betting is.

As a sports bettor it is important to determine what the expected value of a bet is, because that is the difference between profiting over time betting on sports or losing money doing so.

Luckily, OddsJam has an expected value calculator that can do this for you. But, if you want to know the math behind it, then please see below.

The formula is: Expected Value = (Winning implied probability % * profit if bet won) – (Losing implied probability % * stake).

If the calculated number is positive, that means the bet has a positive expected value and if we simulated that event an infinite number of times you would always net a profit.