Over Under: The sports betting term "over-under" explained

With the regular football season just weeks away from start, we have taken the task to explain many sports betting terms, today focusing on the over-under or "over/under". Surprisingly, the over-under would be one of the easiest bets to make at the sportsbooks, whether online or offline. The over-under is a type of bet for which the bookmaker attempts to predict an exact sport statistic for a given game and the bettors would then in turn try to guess whether the statistic would be higher (over) or lower (under) than the sportsbook's prediction.

Most over-under bets relate to the final score in a game and nothing works better than an example. Let's take a football game and the over-under wager on the combined score of the game (called "total"). Let's take the exhibition game NY Jets vs. Philadelphia Eagles. At the online betting website Bookmaker the over-under wager on the total score of the game is posted as follows: Over 35.5 (-110) Under 35.5 (-110). What this means is that the sportsbook predicts that the final score, when combined, would equal to 35.5 points and the bettor has the option to either bet that the total score of the football game will be over 35.5 points or less than (under) 35.5 points.

Now, you may ask "How in the world the total score of a game would be 35.5 points?", glad you asked. Since there are no "half points" in NFL football, this is a good bet to make, as it guarantees that the over-under wager would be either win or lose, i.e. the combined score will be over or under the one posted by the bookmaker. On the contrary, the over-under bet on the Detroit @ Buffalo, which is posted as 34 points, could go "push" or "no action", which means that the combined score of the game actually equals 34 points. You won't lose, but there is no chance to win either.

Let's look back at the Jets vs. Eagles example above and explain the betting odds on the over/under line. In this case, both the Over and Under bets pay out on the same money line, -110. The -110 means that you would win $10 for every $11 wagered, wither way you go with the Over-Under bet. How does the bookie make money in this case? The goal of the odds makers employed at a sportsbook is to have an equal number of bets on both sides of the over-under. So, while there are equal bets on each side of the "total", the bookmaker does not pay equal money, but pays out a dollar less. Here is the example - on the Jets - Eagles game 100 people bet $10,000 that the total will be Over, while 50 people bet $10,000 that the total will be Under, the sportsbook takes in total of $20,000 in wagers on this game's Over/Under. Let's say that the combined final score equals to 28 points, which means that the bookmaker will have to pay the 100 people who bet on Under. Those bettors wagered a total of $10,000, so the sportsbook will have to pay them $19,000 give or take. Since the sportsbook took in $20,000 in bets and paid only $19,000, it came out with $1,000 profit from the Over-Under bet on this game alone.

Ok, this was the beginner's course in Over-Under bets, now let's take it to the advanced. As mentioned earlier, the odds makers at a sportsbook try to have an equal number of bets on both sides of the over-under, which means that the wager oftentimes will move constantly before the game starts. The Las Vegas sportsbooks rule of thumb is that the value of the over/under changes automatically by half a point based on each $1,000 bet. If the Jets vs. Eagles game starts with total of 35.5 points and a $1,000 bet comes in on the Under, the total will automatically adjust to 35 points for the next bettor. This, of course, is done to make sure that there are equal amount of bets on each side of the Over/Under.

There is one more way for the sportsbook to adjust the over-under wagers - instead of changing the "total", the bookmaker will change the payout odds (money line). Here is a good example of this method, found at the online sportsbook BodogLife. The sportsbook is offering the following odds on the Juan Manuel Marquez vs Joel Casamayor WBO Lightweight Title match: Over Rounds 9.5 (-350), Under Rounds 9.5 (+275). In this case the odds maker has decided that the total rounds would equal 9.5 (predict whether or not the fight will go over 1 minute and 30 seconds into the 10th round) and instead of adjusting this number as the bets on the total fight rounds come in, the sportsbook adjusts the payout of the wagers. Looking at the money line on the total rounds, the fight is currently favorite to go for more than 9.5 rounds (Over), since the bookie will pay out $12.86 on every $10 bet, while if the fight last less than 9.5 rounds (Under) the sportsbook will pay out $27.50 on every $10 bet.

Published on 08/27/2008