How it’s calculated
Every format says the same thing: what a bet returns if it wins. Decimal odds include your stake; fractional odds show only what you get on top; American odds show what €100 returns (+) or what you need to stake to get €100 on top (−).
1.85 → 1 ÷ 1.85 = 54.1%
1.85 − 1 = 0.85 = 17/20
−100 ÷ 0.85 = −118
3.00 → 2/1 → +200
1.85 − 1 = 0.85 = 17/20
−100 ÷ 0.85 = −118
3.00 → 2/1 → +200
The probability is 1 ÷ decimal odds. It is the bookmaker’s price, not the chance that something will happen.
Frequently asked questions
How do I convert decimal odds to fractional?
Subtract 1 and write the result as a fraction: 1.85 − 1 = 0.85 = 17/20.
What does −118 mean in American odds?
That you need to stake €118 to get €100 on top of your stake if the bet wins. It corresponds to decimal odds of about 1.85.
Is the probability in the odds the real probability?
No. It’s the probability the bookmaker prices in, with its margin inside.