Understanding odds for point spread betting is simple. Like other wagers, you will have the favorite (marked with the negative – symbol next to their line) and the underdog (marked with the plus + sign next to their line). So, if the Raiders are listed at +120 and the Chiefs are listed at -150, we can look at this line and understand that the Chiefs are the favorites, while the Raiders are the underdogs.
For point spread betting, the same principle applies. Concerning the line, if the Raiders are listed at +7.5 and the Chiefs are listed at -7.5, this means that Kansas City will need to win by 8 points (or more) to cover on the spread. If the Raiders lose by less than 7 points or win the game straight up, this means that they cover the spread.
The example above uses American odds but you will also find point spread betting when wagering on lines listed in decimal or fractional form.
Favorites and Underdogs will still be listed at either – or +, but the actual odds displayed are different. For example, the Mavericks could be listed at +2 (9/10) while the Suns could be listed at -2 (9/10). Fractional odds are the ratio of profit to stake. So, for this wager, you win $9 for every $10 you wager.
As for decimal odds, the line represents the amount one would win on a $1 wager. If the odds are listed at 2.20, you would collect $2.20 for every $1 wagered. On a $50 wager, you would earn $110 if your bet hits, ($50 x $2.20 = $110).