The bookmaker's margin
Turn each price into a chance, 1 divided by the odds, and add them up. In a fair game they would make exactly 100%. In the example they make 104.81%: the extra 4.81% is the overround, and it means that of every €100 you bet you lose €4.59 on average, whichever outcome you pick.
Type in the odds
The figures shown are an example we typed, not any bookmaker's odds. Decimals may be written with a point or a comma.
Type 2 to 40 odds in the format chosen, each above 1.
The chances add up to 104.81%. The overround is 4.81%, and every bet keeps on average 4.59%: €4.59 per €100.
| Odds | Chance in the odds | Chance without the margin | Fair odds |
|---|---|---|---|
| 2.10 | 47.6% | 45.4% | 2.20 |
| 3.40 | 29.4% | 28.1% | 3.56 |
| 3.60 | 27.8% | 26.5% | 3.77 |
The margin is taken out in proportion: each chance is divided by the total. That way every outcome loses the same share of a bet.
The calculation runs in your browser and needs JavaScript. The figures here are the example's.
How it is worked out
Each price becomes a chance: 1 divided by the odds. Their total minus 100% is the overround. A bettor measured at the chances without the margin gets back on average 1 divided by that total of every euro, whichever outcome they back.
A second, independent calculation must give the same figures, or the page is not published.
What this leaves out
- It does not say who will win. Every result is measured at the market's own chances, with the margin taken out.
- Tax on winnings and any charges.