Implied probability calculator
Convert listed odds into the percentage chance behind the price. Use American, decimal, or fractional odds, then compare the same line across formats.
Odds of +150 imply a 40.00% chance before adjusting for market margin.
| American | Decimal | Fractional | Probability |
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Convert odds to probability
Choose the odds format
Select American, decimal, or fractional odds so the calculator reads the price correctly.
Enter one listed price
Add a single outcome price, such as +150, -200, 2.50, or 3/2.
Read the market chance
The result shows the probability implied by that price before any no-vig adjustment.
Implied probability formulas
Positive American odds
Probability = 100 / (odds + 100). A +150 price implies 40.00%.
Negative American odds
Probability = absolute odds / (absolute odds + 100). A -200 price implies 66.67%.
Decimal odds
Probability = 1 / decimal odds. A 2.50 price implies 40.00%.
Implied probability questions
What does an implied probability calculator do?
An implied probability calculator converts betting odds into the percentage chance that the odds represent before removing sportsbook margin.
How do you convert positive American odds to probability?
For positive American odds, divide 100 by the odds plus 100. For example, +150 becomes 100 divided by 250, or 40.00%.
How do you convert negative American odds to probability?
For negative American odds, divide the absolute odds by the absolute odds plus 100. For example, -200 becomes 200 divided by 300, or 66.67%.
Is implied probability the same as true probability?
No. Implied probability is the chance represented by the listed odds. True probability is an estimate of the real chance of an outcome and may differ from the market price.
Use probability with context
No-vig fair odds calculator
Remove market margin after converting each side into probability.
Odds converter
Convert American, decimal, fractional, and probability formats.
What EV means in betting
Learn why probability estimates matter when evaluating a price.
Implied probability is a market-math tool, not a prediction. It does not guarantee value, profit, legality, or safe betting behavior.