What is Expected Value (EV) in Sports Betting?

Some betting concepts and strategies can be difficult to grasp. Especially if you’re only a casual bettor like Granny and wager occasionally on the Grand National, whenever you’re in Las Vegas or every World Cup. In these cases, bettors won’t need to understand strategies like expected value (or EV). However, for many professional sports bettors, the expected value could be the concept around which most of their wagers are based. Please continue reading to discover the meaning of expected value, how to calculate EV, and how it can lead to profitability in sports betting.

What is the expected value?

Despite some claims to the contrary, no one can accurately predict every single outcome of a bet. However, that hasn’t stopped many people from becoming professional sports bettors with the goal of making long-term profits. But rather than blowing on dice or kissing lucky rings, these professionals leverage the concept of expected value whenever they place bets.

So what is EV? It’s the average result you expect to get from a particular bet if it were to be played countless times.

When employing expected value, the goal isn’t to win every bet placed but to make smarter decisions that have a positive expected value. That means betting on odds that are larger than their implied probability. The great thing about expected value is that it can be applied to many online games, such as blackjack, roulette, and even sports betting.

For example, in an online “coin tossing” game, the odds for achieving either heads or tails on one toss is 50/50 (expressed as a fraction) or 2.0 in decimal odds. So with the probability of a coin toss at 2.0, a sportsbook like the Wildz Sports might offer you odds of 2.5 (40/60) regardless of your selection of either heads or tails.

So now that we have the odds (2.5) and the probability (2.0) in place, we’ll next look at how the expected value works in practice.

How to calculate expected value

Let’s imagine that a bettor puts $100 on 2.5 odds at a coin toss, achieving a tails result.

If the bet is successful, the bettor makes $150 profit. If they’re unsuccessful, they only lose their initial $100 stake.

Now multiply the probability of winning by the amount that could be won.

In other words, 0.5 x $150 = $75.

Now, imagine that the bet is unsuccessful.

We now have to multiply the probability of winning by the amount that could be lost.

That is 0.5 x $100 = $50.

Finally, subtract the first value from the second.

($75) - ($50) = $25 of expected value.

That means every time a professional bettor wagers $100 on a coin toss, their expected value is $25.

However, despite concepts such as predictability, there could be some random outcomes, even in a series of coin tosses. If you were to perform 10 coin tosses, you could guess correctly every time. But as the number of tosses increases, say 100, 1,000 or 10,000 coin tosses, the closer outcomes will get to 50/50.

In summary, the expected value is expressed mathematically as:

The probability of winning x the amount that could be won minus The probability of winning x the amount that could be lost.

Expected Value in sports betting

Coin tosses have little to do with sports betting apart from deciding which team or player starts a sports match. But unlike coin tossing, the expected value does. That’s because, in sports betting, there’s a concept called the closing line.

Simply put, the closing line is the last odds on offer before a sports match starts. For example, you can currently get odds on who will win the Super Bowl (LIX) in the NFL even though the game won’t take place until February 9th 2025. So from now until the Super Bowl kicks off, the odds for each team will naturally rise and fall as trades, free agency signings, injuries, form, etc., alter their chances of success.

The closing line will be based on all of these factors and represent the most accurate odds prior to kick off.

But to unearth the expected value in sports betting, a bettor must “beat” the closing line.

Suppose Super Bowl LIX features the Buffalo Bills against the Baltimore Ravens. In the run-up to the game, you can either beat, match or miss the closing line.

Beating the closing line means you’ve got better odds than the closing line or a positive EV
Matching the closing line means you’ve got the same odds as the closing line
Missing the closing line means you’ve got worse odds than the closing line or a negative EV.

From a bettor’s perspective, the ideal situation is to have beaten the closing line. But how does one beat the closing line?

Let’s fast-forward and imagine that Super Bowl LIX is just three hours away. While both teams warm up on the field, Zay Flowers, the Ravens’ best wide receiver, pulls a hamstring and is immediately ruled out of the game.

In a contest that was considered evenly matched prior to the injury, the odds on the Bills winning could theoretically drop from, say, 2.5 to 1.8 (or from +150 to -125).

For quick-thinking bettors, beating the closing line would mean betting on the Bills to win at 2.5 (+150) before sportsbooks can change their odds to 1.8 (-125). In many cases, a bettor may have anywhere from a few hours to minutes to beat the closing line. For professional bettors, these small time windows represent opportunities to win big. In other words, betting on larger (and better) odds than those represented in the closing line. That’s how you could achieve expected value (EV) and potentially a profit in sports betting.