Odds converter
Convert one price between American, decimal and fractional odds, and read the implied probability it carries.
A price cannot be zero, and cannot sit between -100 and +100.
Converted price
How it is calculatedOpenClose
A positive American price of A returns 1 plus A over 100 per unit staked. A negative price of A returns 1 plus 100 over the absolute value of A. Implied probability is 1 divided by that decimal return. Fractional odds are the profit part of the decimal return written as a fraction.
- The implied probability of a price is its break-even among decided outcomes, so it includes the book's margin. It is not the market's fair estimate of the outcome.
- Fractional odds show the profit part of the decimal return. Where no simple fraction reproduces the price exactly, the nearest one is shown and labelled.
- An even money price is written +100 by convention, so a -100 entry converts back as +100.
Worked example, illustrative
A standard two way price
- 1A price of -110 returns 1.9091 per unit staked, stake included.
- 2In fractional form that is 10/11.
- 3The implied probability, the break-even, is 52.38%.
These figures are an illustration of the formula, not a claim about any real market.
Related guidance
Research only. This tool does arithmetic on numbers you type. It does not place bets, submit entries, estimate a probability for you, or tell you what to risk. If gambling stops being fun, call 1-800-GAMBLER.