Betting odds are a way to quantify how likely a certain event is to happen. Odds themselves are a way to predict the probability of an event, and betting odds are a way to put a dollar amount on each probability.
For the most part, sport betting odds are based on teams that are favorites and teams that are underdogs. Favorites are by definition more likely to win, so sportsbooks will adjust the odds to make it closer to even odds to win money.
Sports bettors will largely be dealing with point spread bets and moneyline bets, which we will explain below.
Moneyline bets are found in virtually every sport and essentially tell you the ratio of your initial bet to the payout. For example, let’s say the Yankees are a a heavy favorite. A sportsbook may put their moneyline odds at -300, which means you would have to wager $300 in order to win $100 because they are so likely to win. Or a sporsbook may tab the Mets as a big underdog, and put their moneyline odds at +400. That means your $100 bet could net you $400 if the Mets pull off a miracle.
The other common bet type is the point spread bet, which has different variations in sports like baseball, hockey, and soccer. A point spread is basically the margin that a favorite has to win by in order to “cover,” or pay out. So if the Patriots are a -7 favorite to win, they must win by 8 or more points for you to win your bet, which a 7-point win would be a “push,” or draw. On the favorite side, if the Dolphins are a +4 underdog, you can still win money even if they lose, as long as they lose by 3 or fewer points.
All NFL games have a “line.” Each game has a point spread, which is a way for sportsbooks to even out the competition. So if the Bears are a heavy favorite, they may “give up” 8 points at -8 odds, which means they have to win by at least 9 to pay out. This means in cases of big point spreads, many bettors can wager on heavy underdogs at relatively even odds since the underdog playing the Bears doesn’t even have to win, they just have to lose by less than 8 points.
The other line every game will have is the moneyline. Instead of having the Bears “give up” points, this is a straight up bet that will simply pay out much less to a favorite. So if the Bears are at -325, you would have to wager $325 just to win $100. But the team playing the Bears, at say +250 odds, would pay out $250 on a $100 bet.
NBA odds work similarly to NFL odds. Each game has a point spread and a moneyline, and you can wager on either or both. All sports also have a variation of an “over/under” bet, in which you can wager on whether the final score will be higher or lower than the combined score projected by online sportsbooks. The over and the under will each have their own moneyline, based on the probability of either event.
MLB odds are a bit different than the NBA and NFL because instead of point spreads it has “run lines,” which basically sets the spread of each game at 1.5 runs. So in a runline bet, the favorite would have to win by 2 runs or more while the underdog must win or lose by no more than one run for you to win.
NHL odds are similar to MLB odds except instead of a “run line” they have a “puck line,” which also sets the spread of every game at 1.5 goals. This is done as a way to even the playing field, though most bets are placed on the moneyline.
Soccer odds are akin to both NFL betting and NHL betting. Similar to the NHL, it has a “goal line” instead of a point spread. The goal line is usually around 0.5 since games tend to be low scoring but it is similar to the NFL and NBA in that it differs from game to game. So in a very uneven matchup the goal line could be 2- or 2.5-goals.