How to read football odds:
from odds to chance

What do football odds tell you?

Decimal odds such as 1.55, 2.10 or 3.40 are the easiest to work with. The lower the odds, the more likely the outcome is judged to be. The higher they are, the less the market believes in it.

Odds do not tell you what will happen. They tell you how the market sees the match at a given moment, and they move until kick-off.

How do you turn odds into a chance?

It is a division: 1 ÷ odds. The result is called the implied probability: the chance contained in the odds.

For odds of 1.80, divide 1 by 1.80: you get about 56%. With a calculator, it takes five seconds.

What is the bookmaker margin?

Take a match with three outcomes. The odds below are an invented example, not those of a real match.

The three chances in a match always add up to 100%. Here they reach 104.8%. The extra 4.8 points are the margin: the share the bookmaker keeps for itself. It is built into every price.

How do you remove the margin to see the real chance?

Divide each percentage by the total: 47.6 ÷ 1.048 = 45.4%. Do the same for the other two. The total falls back to 100%: these are the chances the market assigns, margin removed.

How do you know if odds are worth a look?

There are two uses. Removing the margin lets you read the market's opinion: 45.4% for the home win in the example. Judging a price is different: you keep the margin, because that is the price actually on offer.

Odds are interesting when the chance you estimate beats the chance they contain, margin included. Do you rate the home win at 50%? The 2.10 odds contain 47.6%: your estimate sits 2.4 points above.

Everything rests on the quality of your estimate. If it is wrong, the gap is wrong. This gap has a name, the value bet, explained in our value bet guide. A favourable gap does not raise the chance that the bet comes in: it only says the odds pay more than what you judge fair.

Why do two sites show different odds?

Each bookmaker sets its own price and its own margin. For the same match you might see 2.05 on one site and 2.15 on another. The margin also changes from one market to another: it is often smaller on a big match than in a small league.

It is better to compare two prices with the margin removed than to trust a single one.

What about fractional or American odds?

You will meet 5/2 or +250 on some sites. Both are the same price as decimal odds of 3.50. To get back to decimal: 5 ÷ 2 + 1 = 3.50, or 250 ÷ 100 + 1 = 3.50. After that, the 1 ÷ odds division works as usual. No format is better than another: only the language changes, the price stays the same.

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