The probability necessary to win at a given spread is not always something the novice gambler is aware of. This is important because novice gamblers get tempted to bet on the -200 favorite because he/she knows it will likely win the game. What they don't know is that if the given -200 favorite does not have a 66.6% or better chance of winning, it is a losing proposition over the long haul.
How To Calculate For Favorites
A favorite is a team with a negative spread like -105, -150, etc.
Take the absolute value of the spread and divide by itself plus 100. For example, for an -150 team, take 150/250 = 60%. To pull even, our -150 favorite must win 60% of the time.
How To Calculate For Underdogs
Take 100 and divide by 100 plus the spread. For example, a +150 team, take 100/250 = 40%. To pull even, our +150 dog must win 40% of the time.
List of Break Even Percentages- -200: 66.7%
- -180: 64.3%
- -160: 61.5%
- -140: 58.3%
- -120: 54.5%
- +100: 50.0%
- +120: 45.4%
- +140: 41.7%
- +160: 38.5%
- +180: 35.7%
- +200: 33.3%
If you find yourself betting on a favorite, check the break even percentage to ensure that the bet is a profitable one. If you are looking to bet on baseball over the long haul, keeping an eye on the break even percentage is important. Being able to predict a team's probability of winning is equally as important.