Implied Probability Calculator
Convert betting odds from any format to implied probability. Enter American, decimal, or fractional odds to see the bookmaker's implied probability of the outcome, plus conversions to all three formats.
Every set of betting odds implies a probability. Understanding implied probability helps you compare odds across sportsbooks and spot value bets where the true probability exceeds what the odds suggest.
Conversion Formulas:
American to probability:
- Negative odds (favorite): p = |odds| / (|odds| + 100)
- Positive odds (underdog): p = 100 / (odds + 100)
Decimal to probability:
- p = 1 / decimal odds
Fractional to probability:
- p = denominator / (numerator + denominator)
Example: American odds of -150 mean the bookmaker implies a 60% chance. If your analysis says the true probability is 65%, that is a value bet. If you think it is only 55%, the odds are not in your favor.
What About the Vig?
Bookmakers build in a margin (the "vig" or "juice"). When you add the implied probabilities of all outcomes in a market, the total exceeds 100%. The excess is the bookmaker's edge. To find the "fair" probability, divide each implied probability by the total of all outcomes.