Regardless of the odds format, sports betting odds reflect a sportsbook’s opinion of the probability of something happening. Being able to assess that will help you to make smart decisions when considering whether a bet is good value or not.
For example, a +200 bet (3.00 in decimal odds, 2/1 in fractional odds) is expected by the sportsbook to be successful once every three times, meaning its implied probability is 33.3%.
A bet at +400 odds (5.00 in decimal odds, 4/1 in fractional odds) is expected by the sportsbook to be successful once every five times, meaning its implied probability is 20%.
By understanding how sportsbooks view their implied probability of a bet winning, you can compare their view to your own. If you feel the probability of winning is higher than the implied figure represented by the odds, you can decide to back your judgement and place a bet.