Convert odds
Use a period for decimals. American odds use +100 or higher, or -100 or lower. Fractional odds use a ratio such as 5/2. Changing format loads an example.
- Implied probability
- 60%
- Decimal odds
- 1.666667
- American odds
- -150
- Fractional odds
- 2/3
Implied probability is the break-even rate before fees. It is not an independent forecast. Results do not remove bookmaker margin or include platform fees. Values are rounded for display; 0% and 100% do not have finite equivalent odds in this converter.
Enter odds or a probability in the converter above. It displays equivalent decimal, American and fractional odds, together with the implied probability. Changing the input format loads an example; replace it with your own value.
Formulas and conventions
Decimal odds include the returned stake. Fractional odds describe net profit relative to stake. Positive American odds state profit on a $100 stake; negative American odds state how much must be risked to make $100 profit.[1]
| Input | Implied probability as a decimal | Example |
|---|---|---|
Decimal odds D > 1 | 1 / D | 2.50 gives 40% |
American odds A >= 100 | 100 / (A + 100) | +150 gives 40% |
American odds A <= -100 | abs(A) / (abs(A) + 100) | -150 gives 60% |
Fractional odds N/D | D / (N + D) | 5/2 gives about 28.5714% |
For the negative-moneyline example, 150 / (150 + 100) = 0.60. Using -150 / (-150 + 100) would incorrectly produce 300%. The sign cannot be discarded without also changing the denominator correctly.
Probability is not a prediction
Implied probability is the break-even winning rate before fees under the stated odds. It does not establish how likely the event really is. Prices from a bookmaker can include a margin; converting each side independently does not remove that margin. Fees can also raise the break-even probability of a prediction contract.
The converter accepts probabilities strictly between 0% and 100%, decimal odds above 1, conventional American odds outside the interval (-100, +100), and positive fractional ratios. Zero and certainty are excluded because they do not have finite equivalent odds across all these formats. Displayed values are rounded; fractional approximations are marked.
Read understanding prices for settlement examples and finding mispriced markets for comparing a forecast with a tradable price.
References
- DraftKings Sportsbook. How to Read Odds. Operator explanation of American and decimal odds and implied probability. Accessed October 13, 2026.