The three odds formats
Decimal (European) shows the total return per unit staked. Fractional (British) shows profit relative to the stake, like "3/2". American (moneyline) uses positive numbers (profit per 100 staked) or negative numbers (stake needed to profit 100).
Conversion formulas
| From | To decimal |
|---|---|
| Fractional a/b | decimal = a/b + 1 |
| Positive American (+X) | decimal = 1 + X/100 |
| Negative American (−X) | decimal = 1 + 100/X |
Educational use
This tool is purely mathematical, meant to understand and compare how different markets express the same odds — it is not an encouragement to bet.
Frequently asked questions
Which format is most common in the US?
American (moneyline) odds are the standard in most US sportsbooks.
What does decimal odds of 2.00 mean?
It means for every 1 unit staked, you get 2 back (double) if you win — equivalent to a 50% implied probability.
What is implied probability?
It's the chance of the outcome happening according to the odds offered, calculated as 1 divided by the decimal odds, as a percentage.