How Expected Value Works in Sports Betting

Expected Value Text Image With a Sportsbook Background

You won’t need to try hard to lose money at sports betting. Many wishful gamblers devote years honing their craft only to end up losing money for their efforts.

Even a loss can provide you with several hours of heart-wrenching entertainment.

But for the people wanting to turn a profit at sports betting, it requires great discipline.

Discipline and an elementary grasp of math can take you far, in fact.

Know Your Worth

A group of bettors considers themselves “positive E.V.” sports bettors — as in “positive expected value.”

I’ve read dozens of articles on the subject, and they’re just too complicated.

Or maybe I’m just not sharp enough to follow adequately.

I’m sharp at math and still have trouble. My brother, on the other hand, has taken his shoes off to count to 11.

I want to provide a sufficient explanation of how expected value works in sports betting that my brilliant, if not mathematically inclined, brother could easily digest and apply.

Hopefully, I’ll allow newer gamblers with a fundamental understanding of the expected value and provide veteran sports bettors with a helpful refresher.

Sports Betting and Probability

You surely remember taking what seemed like endless math classes in high school or college. During my junior and senior years of high school, I had two math classes per semester. Sheesh, I was glad to have that over and done.

Some of the classes dealt with statistics and probability. You may not remember because, much like countless others, you tuned out almost immediately. You are in the vast majority. Perhaps you paid close attention, and maybe you were even a self-proclaimed math geek, but that was 20+ years ago, and the lessons have been swallowed up by other information.

No matter why the information hasn’t stuck, we use most of it every day without even realizing it.

You don’t need a wall of diplomas and years of grad school to understand predictive sports modeling. The high school classes we all daydreamed through are more than enough to comprehend the basics. You should know this; it’s nearly impossible to win money from sports betting without a basic probability grasp.

I am shocked by the number of gamblers that implement strategies that largely ignore probability’s core principles.

If you are among the mathematically able gamblers with a firm knowledge of probability, don’t fret.

There remain some critical keys to success that are often overlooked or forgotten. Even if you consider yourself an expert, it may be beneficial to review the basics.

After all, Tiger Woods is hitting the driving range every day, hitting 7 irons.

I’d say he’s been an expert at hitting a golf ball for the last 40 years.

My goal here is to keep it simple for you when it comes to E.V. (expected value.) This won’t be the be all end all examination of expected value you could attempt to decode. This will be a concise and easily understood breakdown for the casual sports bettor looking to up their profits.

Probability and Expected Values

Sports can be wildly entertaining.

What makes sports so fascinating to most fans?


Not knowing what will happen on the field and having no control over the events keeps us locked in for every second of the action.

I’ve seen 80-foot buzzer-beaters, Tom Brady mount an impossible second-half comeback to win another Super Bowl, and I’ve even watched Randy Johnson clip a bird out of the air mid-flight with a fastball.

This uncertainty makes one thing clear.

One fact about sports betting is that there’s no such thing as an absolute lock when it comes to the winner.

Quarterback Tom Brady Playing in Super Bowl 51

Not even a group of toddlers would have a true 0 or 1 probability in a game versus the NBA’s Dream Team. So, the whole game of sports betting is coming up with a number somewhere between 0 and 1. This number is representative of the likelihood something may occur. Most often, a particular team is winning or scoring a set number of points.

Once you can successfully do this with a modicum of accuracy, you can contrast it to the implied odds the sportsbooks are giving and possibly see that you have an edge.

Many people hear words like calculate and immediately become discouraged. Don’t worry; calculating the implied probability is simple.

Each time a sportsbook sets a line, it implies a certain probability of a specific bet winning. It is making the statement that bettors would draw even money should they win a certain percentage of contests over time.

I’ll use a coin flip to illustrate this idea. On the flip of a coin, the line would be +100. This implies a 50% probability of either result.

After you have grasped the simplicity of the concept and begin converting lines to probabilities, you have the necessary tools to deduce if a bet has a positive E.V.

It’s as Simple as a Coin Toss

To become a better sports gambler you need a solid enough foundation to predict the probability of a specific outcome accurately — as I stated above, typically a winner or the scoring of a set number points.

The number that you come up with should be compared to the lines offered by the sportsbooks.

This is how you should calculate +EV.

Do you expect to make a profit if you win the bet over and over, almost in to perpetuity? If you answer “yes” to this question, you have found positive expected value and are well on your way to winning at sports betting.

Think of it like this:

The casino offered you “heads” on a coin flip at +110 odds.

The +110 implies a probability of 47.6%.

This is a tremendous +EV because the true probability of landing heads is 50%. You are going to lose the bet an equal amount as you win.

However, you are getting more cash on a win than you are giving away on a loss. Over time you will make a tremendous amount of money with this model.

This won’t ever be offered. Any sportsbook or casino that gave this type of action would go bankrupt in double time.

Losers Can Win for You

You can find some fantastic values if you look closely. Remember, we aren’t looking for 100% locks because we’ve already established that they don’t exist.

For example, you may find a tremendous underdog in MLB. Imagine that the L.A. Dodgers and perennial Ace Clayton Kershaw face a beat down and injury-plagued Houston Astros in a meaningless late-season game.

You have found that Houston has only a 34% chance of beating the Dodgers. That’s not low, but it is far from good. But the sportsbooks give the Astros even fewer chances of winning and the line closes at +351-.

This translates to a measly 22% probability of Houston winning. This giant discrepancy would be the perfect opportunity to exploit that edge. You should take these risks and bet on the team you may fully expect to lose.

View of Dodgers Stadium From the Stands


Because you are receiving a tremendous value, you would make a profit long term if you were to get this action continuously.

The point here is always to follow your model. If you have a team that is less than 50% probability of winning but are getting +EV, you take the bet.

I see many gamblers waiting around for the sure thing, and they grow increasingly frustrated as their bankroll dwindles to a firm zero. They fail to understand that sports betting is a long game and need small incremental wins to succeed.

Don’t misinterpret this as me implying you should only bet on underdogs. Far from that, I encourage you to look for the best value. I only want you to understand that making value bets is more than merely taking your best guess on what team will win a game.


Profitable bettors must regularly bet on the team they expect to lose the contest. Teams that have a below 50% probability of winning that is. The savvy sports bettor appreciates that over a greater sample size will incur a greater +EV.

This post should have provided you with the basic building blocks to begin understanding how expected value works. For some of you, this may have been a welcome refresher on the subject. Either way, I appreciate your attention. For those of you that fell into autopilot as soon as you saw the word math, the bell just rang.

Class dismissed.