Expected Value (EV) Calculator

Expected Value is probably the single most important concept in sports betting, but a lot of people skip right past it. They focus on win rates or units won, which are fine metrics, but EV tells you whether you're actually making smart bets or just getting lucky.

Here's the core idea: EV is what you can expect to win (or lose) on average if you made the same bet thousands of times. A single bet might win or lose, but over the long haul, positive EV bets make money and negative EV bets lose money. It's that simple.

The tricky part isn't the math—it's honestly pretty basic. The hard part is accurately estimating the true probability of outcomes. That's where your edge comes from. If you're better at assessing probabilities than the bookmaker's odds suggest, you can find positive EV bets all day long.

The EV formula looks intimidating at first, but break it down and it makes total sense:

EV = (Probability of Winning × Amount Won) - (Probability of Losing × Amount Lost)

Let's say you're betting $100 on a team at +150 odds. You think they have a 50% chance of winning (that's your assessment, not the bookmaker's). If they win, you profit $150. If they lose, you lose $100.

Plug it in: (0.50 × $150) - (0.50 × $100) = $75 - $50 = $25

That's a positive $25 expected value. Over the long run, if you could make this exact bet 100 times, you'd expect to be up $2,500. Will you win exactly 50 times? Probably not. But the math says this is a profitable bet.

Here's what trips people up: you can make a perfect +EV bet and lose. You can even make ten perfect +EV bets and lose all ten. Short-term variance is brutal, and it's why bankroll management matters so much.

Think about a coin flip where you get $1.10 for heads but only lose $1 for tails. Massive positive EV—you should take that bet every time. But you could still easily lose five flips in a row and be down $5. The bet was still correct. You just need a big enough sample size (and bankroll) to survive the variance.

This is why professional bettors track thousands of bets and look at their performance over months or years, not days or weeks. A few losing streaks don't mean anything if your EV is solid. But if you're betting negative EV, even a winning streak is just borrowed time.

Finding +EV bets comes down to one thing: having a more accurate assessment of probability than the market. There are a few ways to do this:

Specialization: Pick a niche—maybe a specific league, team, or bet type—and become an expert. The more you know about something, the better your probability estimates will be compared to a bookmaker covering hundreds of sports.

Line shopping: Different books have different odds. If your model says a team has a 55% chance of winning, finding +105 odds instead of -110 can turn a marginal bet into clear +EV. This compounds over time.

Timing: Lines move based on betting action, injuries, weather, etc. Sometimes you can catch a line before it moves if you're quick. Early week NFL lines or overnight market movements can create temporary inefficiencies.

Using better data: If you have access to advanced metrics, player tracking data, or better injury information than the general public, you can spot edges. This is why some sharp bettors pay for premium data services.