Implied Probability Calculator
Derive the true probability priced into one or more sets of bookmaker odds.
How to Use This Calculator
- Set the odds format: Decimal, Fractional, or American
- Input odds for a minimum of two outcomes (e.g., Team A and Team B)
- Append additional outcomes where required (e.g., a draw in soccer)
- Read the implied probability per outcome, the aggregate probability, and the bookmaker margin
When the aggregate implied probability exceeds 100%, that excess is the bookmaker’s margin.
Formula
Implied Probability from Decimal Odds: Probability = (1 / Decimal Odds) x 100%
Bookmaker Margin: Margin = Total Implied Probability - 100%
No-Vig (Fair) Probability: Fair Probability = Implied Probability / Total Implied Probability
Frequently Asked Questions
What does implied probability mean?
Implied probability is the outcome likelihood derived from the odds. Because it embeds the bookmaker’s margin, the sum across all outcomes always comes out above 100%.
How is the bookmaker margin defined?
The bookmaker margin, also called vig or juice, is the gap between the summed implied probabilities and 100%. That gap is the bookmaker’s built-in profit.
How are value bets identified?
When your estimate of an outcome’s true probability exceeds the implied probability priced into the odds, the wager carries positive expected value.