Odds Calculator
Calculate the odds of an event occurring based on probability, or convert between different odds formats (fractional, decimal, American).
Published by:
isCalculator Editorial Team
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How to use this tool?
This calculator converts between probability and three common odds formats. Follow these steps:
- Enter any one value in the fields below:
- Probability (%): A number between 0 and 100 (e.g., 25 for 25%).
- Fractional Odds: Format like
3/1(numerator/denominator). - Decimal Odds: A number ≥ 1 (e.g., 4.0).
- American Odds: Positive or negative number (e.g., +300 or -300).
- Click the Calculate button.
- View the Results section showing all four formats converted from your input.
The calculator automatically detects which field you filled and computes the others. Ensure fractional odds use a slash (e.g., 7/2) and American odds are not zero.
Previous Results
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Frequently Asked Questions
Odds represent the likelihood of an event occurring. They can be expressed in fractional, decimal, or American formats.
Probability (as a decimal) can be converted to decimal odds by taking 1/probability. Fractional odds are (1/probability) - 1. American odds depend on whether probability is above or below 50%.
Fractional odds show profit relative to stake (e.g., 3/1 means you win 3 for every 1 staked). Decimal odds include the stake (e.g., 4.0 means you get 4 back for every 1 staked).