How to understand over/under betting and wager on totals
Milwaukee puts up a lot of points and sees high totals thanks to Giannis Antetokounmpo. Photo by Morry Gash/AP.

Wagering on the total score of a game is one of the most popular markets offered by sportsbooks. This is known as over/under betting.

Operators will assign a number that the two teams have to combine to score and you can either bet the over or the under on it. In other words, you can wager on whether they will fall short or eclipse the number that is set by the provider. 

That’s how the total gets its over/under name, which is also referred to as the O/U for short. All three of these betting terms mean the same thing. 

Over/under odds

Like point spreads, the odds for a total are usually the same or quite similar for both the over and the under. This number is generally set at -110 or somewhere within this range. That's especially true for NBA and NFL totals.

You will sometimes see the odds shaded to one side. An example of this would be odds of -115 for the under and -105 for the over. The odds typically don't stray too far away from that in either direction unless betting on alternative totals. But the sports where you do see greater variance are the NHL and MLB.

At the standard -110 odds, you would have to wager $110 to make a $100 profit. 

Alternative totals

Alternative totals are numbers, in either direction, that differ from the main point total set by the sportsbook. The odds reflect the change in number and would be different from the main -110 line.

You can assume more risk on an unlikelier outcome for a larger payout or accept more juice (the cut that goes to the operator for taking your bet) by placing a wager that has a greater probability of occurring.

For instance, an operator could set a 222.5 total for a Toronto Raptors and Boston Celtics game at -110 odds, meaning 223-plus points would be required for your best to cash if you took the over. An under bet would be successful if the teams scored 222 points or fewer.

But most operators allow you to bet on other lines, too. This could be a total of 219.5 at -145 odds or 226.5 at +120. Odds of -145 would require a $145 wager to win $100, while you'd win $120 on a $100 bet at +120.

Over/under betting in the Big Four

Since scoring can vary significantly across the major North American sports, totals look different depending on which league you are betting on. 

The NBA, of course, comes with the largest totals, which are typically set between 200-230 points. Following the NBA is the NFL, where the O/U usually sits between 40-50 points.

MLB sees totals that, for the most part, fall in the 7.5-10.5 range. The NHL, meanwhile, has the least discrepancy between numbers and the O/U is usually 5.5 or 6.5. NHL totals rarely go above 6.5, while MLB has a lot more factors that go into setting the number. 

Games played at Colorado's hitter-friendly Coors Field consistently see the highest MLB totals. Photo by David Zalubowski/AP.

Two things especially make MLB unique in this regard. For starters, ballparks have an impact on the O/U, as some stadiums are strong offensive environments while others suppress runs. Secondly, the quality of the starting pitcher plays a major role in not only determining the favourite but also what the over/under is. 

Totals can vary considerably from game to game, especially in the NFL and NBA, with factors such as how good a team is offensively or defensively impacting the number. NBA teams average between 100-120 points per game, so rarely will you see totals set below 200. You will, however, see the number creep past 230 in a game between two high-powered offensive teams.

Weather plays a part, too, in over/under betting. Rough conditions can have an adverse effect on offence which can bring down the O/U number in NFL betting.

In addition to game totals, you can also bet on a specific team’s total in all of the major sports. Operators will give you the option of making an over/under bet on just the home or road team's output.

NorthStar Bets editorial Insiders have no influence, direct or otherwise, over the setting of odds advertised on our platforms.