Long-term profit in sports betting comes from consistently finding and exploiting "value" in the odds. This means you are getting better odds than the true probability of an outcome.
Calculating Implied Probability
The first step is to convert odds into implied probability. For American odds, the calculation is simple. For positive odds: 100 / (Odds + 100). For negative odds: |Odds| / (|Odds| + 100). If your assessment of the true probability is higher than the implied probability, you have found a value bet.
Shop for the Best Lines
Different sportsbooks will offer slightly different odds on the same game. Having accounts at multiple books allows you to "line shop" and ensure you are getting the best possible price for your bet. This small edge accumulates significantly over time.