Implied Probability Calculator
Convert betting odds to implied probability.
Implied probability is the win chance baked into betting odds.
How the Math Works
Implied probability converts betting odds into a percentage chance of an outcome occurring, based on the amounts wagered. For decimal odds, the formula is 1 divided by the odds multiplied by 100 (e.g., odds of 2.0 equal 50% implied probability). For American odds, the calculation differs: positive odds use 100 divided by (odds plus 100), while negative odds use the absolute value of odds divided by (absolute value of odds minus 100). This transforms risk-reward ratios into intuitive likelihood estimates that help standardize comparisons across different betting formats.
Practical Applications
To use this calculator, simply input your betting odds in either decimal or American format. Enter decimal odds like 1.85 or American odds like +150/-120 directly into the tool, and it will instantly output the corresponding implied probability percentage. This is particularly useful when comparing betting lines across different sportsbooks or evaluating whether a bet offers positive expected value by contrasting the implied probability with your own estimated likelihood of the outcome.
Day-to-Day Use
Understanding implied probability sharpens your decision-making whenever you encounter odds-based situations, from sports betting to fantasy sports contests, insurance policy evaluations, or even financial investment opportunities where payout probabilities matter. It helps you quickly assess whether a quoted probability feels accurate or if you're being offered favorable or unfavorable odds, enabling more rational choices in any scenario involving risk and reward.
Worked example
+150 American → 40% implied probability.
FAQ
Why don't they add to 100%?
The bookmaker's margin ('vig') makes the implied probabilities sum above 100%.