Implied Probability Calculator

Implied probability represents the likelihood of a specific outcome as suggested by its given odds. The mathematical formula depends on whether the American odds are positive or negative. For positive odds (representing underdog scenarios), the formula is: Probability = 100 / (Odds + 100). For negative odds (representing favorite scenarios), the formula is: Probability = |Odds| / (|Odds| + 100). These equations translate raw market pricing into a clear percentage between 0% and 100%.

Imagine you are evaluating a sports match where Team A is a heavy favorite with American odds of -200, and Team B is the underdog with odds of +150. To find the implied probability for Team A, take the absolute value of the negative odds: 200 / (200 + 100) = 200 / 300, which equals 66.67%. For Team B, apply the positive odds formula: 100 / (150 + 100) = 100 / 250, which equals 40.00%. Note that the sum of these probabilities is 106.67%, with the extra 6.67% representing the market's vig or house edge.

Always account for the vigorish (the bookmaker's commission) when analyzing a complete set of odds, as the total implied probability will often exceed 100%. Ensure you correctly distinguish between positive and negative signs when inputting your data, as a misplaced sign completely reverses the underlying mathematical operation. Use this calculator to compare odds across multiple platforms to identify discrepancies and genuine statistical value.