How does an Over/Under Work?

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Contributor, Benzinga
June 2, 2021

Whether for fun, for profit or both — betting on sports makes it more engaging. With laws and regulations loosening, betting is becoming one of the more popular pastimes.

Like many concepts involving game theory, betting is easy to understand but hard to master. Before trying out more complicated strategies, you should familiarize yourself with the basics. So, read on to explore what over/under betting is and why it is so popular.

What is Over/Under?

Over/under is a type of wager where a bettor attempts to predict if a certain statistic will be over or under a set threshold in a given game.

Over/under became a popular concept because it’s easy to apply it in everyday life. You’ve applied it yourself — setting imaginary odds on anything between the boss berating coworkers or waiting for that one friend who is always late.

Over/under a threshold is an arbitrary statistic from the game. It varies by the sport, but some of the most notable examples include:

  • Basketball: The most popular is a total number of points. Others include rebounds and assists.
  • Tennis: Most commonly for the number of sets or games. In a 3-set game, this means betting on over/under at 2.5 sets — anticipating that the game will go into a 3rd and final set.
  • Football: This is over/under on the total score.
  • Soccer: Usually this is over/under on the total number of goals. Other popular options include corners, throw-ins and yellow/red cards.
  • Boxing: Bets are made whether matches go over/under in a certain number of rounds.

Where is the Over/Under Most Common?

While applicable to almost any sport, betting over/under is the most common in American football and basketball.

For example, a match between the Dallas Cowboys and Tampa Bay Buccaneers has an over/under the line of:

Over 53.0, -110

Under 53.0, -110

So, a $110 bet would net you $100 if the match score is over 53 points, and an equally sized bet would earn $100 if the score is below 53 points.

A basketball game might look similar, albeit with a different threshold.

For example, a match between Washington Wizards and Philadelphia 76ers has an over/under the line of:

Over 230.0, -110

Under 230.0, -110

While the odds are identical in the previous match, the basketball threshold is much higher for obvious reasons. Game scores are much higher in comparison to football.

Is Betting the Over/Under Smart?

Betting over/under can be a good strategy if it relies on the proper research. Yet, even with the research, you should always think about who else knows what you know. If it is publicly known information, the odds have likely already adjusted to represent the new situation.

Betting over/under blindly will not be profitable. If you look at the odds in the examples above, -110 on both sides represents a 10% edge that the bookie has.

Can you Find a Sure Thing?

Betting is a game of probabilities, and there is always a chance that you will lose the bet. A horse will throw the jockey, a star quarterback will skip a game to rest, the best point guard of the league will roll an ankle during the warmup — the reasons why things can go wrong are numerous.

The closest to a “sure thing” would be to solicit information or engage in match-fixing. Yet, even this highly illegal activity is not 100% safe. The rise of big data collection and processing enabled bookies to track suspicious bets and odd changes in their systems. Any significant discrepancies are likely to raise suspicions and launch investigations.

Although a sure thing doesn’t exist, a “safe bet” concept is for real. A safe bet is an arbitrage that arises when there are betting line discrepancies.

Take the example of the basketball game from above that has an over 230.0 at -110. Now, if any other sportsbook offered over 230.0 at + 111, you would be able to bet on both sides and still come out $1 ahead.

Safe bets still exist, but they are rare as any arbitrage opportunities close fast in the digital information era.

Can you Push?

Push happens to your bet when it expires as a tie. Pushing the over/under is incredibly rare, and most bookies do not feature such odds.

Yet, they do happen from time to time. In some sports, over/under pushes are impossible per current rules. For example, a tennis game will always be over/under a certain number of completed games.

In other sports, push can be as much as 1 second. For example, in MMA, if you bet over/under 1.5 rounds, the action would have to be stopped precisely at 2:30 into the second round for the bet to be a push. Thus, a 2:29 would be a win for under and 2:31 a win for over.

Betting is one of the fastest-growing sectors. If you are looking for a sports betting platform, check out the offer from our list below. However, be sure to check if they are available in your state. 

There is no Free Lunch

While in the short run, anyone can get lucky. Eventually, luck ceases to be a factor.

Professional gamblers like Bill Benter know this very well. Back in the ’90s, Benter wrote an algorithm to bet on horse races. Eventually, it was tracking over 120 factors per horse.

Competing with the billionaire gamblers like Benter is not an easy task. Betting is a game of probabilities and it takes a lot of work to get it right.

In the end, an occasional bet can be considered as recreation… a price we pay when we care to make things interesting. Yet, if you are seriously interested in putting your money down, be ready to crunch through the numbers as there’s no free lunch in the big data world.

Frequently Asked Questions


How do you read an over/under?


Odds for over give you the return on betting that the combined score or some other statistic for the game or match will be OVER the threshold. Conversely, the odd for under gives you the return on betting that the same will be UNDER that threshold.

For example, odds for Roger Federer’s match are as follows:

  • Over 20.5 games: -107
    Under 20.5 games: -128

Meaning, assuming you are correct, to win $100, you need to bet $107 on over or $128 on under.


What happens if the over/under is exact?


If over/under falls on the exact number of the threshold, the bet is declared a tie and all bets are refunded.