Guide · updated 2026-10-05
How to turn football odds into probabilities
Decimal odds of 2.50 imply a 40% chance (1 ÷ 2.50). Add up the implied chances of every outcome, divide each one by that total, and you have the market's fair probabilities with the bookmaker's margin removed.
Step 1: implied probability
Decimal odds show the total return for a one-unit stake. The implied probability is 1 divided by the odds: 2.00 implies 50%, 4.00 implies 25%, 1.25 implies 80%.
Step 2: find the margin
For a home, draw and away market the implied probabilities add up to more than 100%. The excess is the overround, the bookmaker's built-in margin. Lower margins mean prices closer to the market's true view.
Step 3: remove it
Divide each implied probability by the total. The results add up to 100% and can be compared directly with a model. Other methods spread the margin unevenly (for example the power and Shin methods), but proportional scaling is transparent and is what our match pages use.
Worked example: Arsenal vs Leeds United
Prices from leovegas on our Arsenal vs Leeds United page. The implied total is 106.8%, so the margin is 6.8%.
| Outcome | Decimal odds | Implied (1 ÷ odds) | Fair, margin removed |
|---|---|---|---|
| Arsenal | 1.38 | 72.5% | 67.8% |
| Draw | 4.75 | 21.1% | 19.7% |
| Leeds United | 7.50 | 13.3% | 12.5% |
Figures are recalculated from the latest stored prices; the match page may average several bookmakers.
Why it matters
Fair probabilities let you compare a price with any other estimate on the same scale. Our match pages put the de-vigged market next to the Dixon–Coles model; the accuracy guide shows which has been closer to the results.
Common questions
What is the implied probability of decimal odds?
Divide 1 by the decimal odds. Odds of 2.50 imply 1 / 2.50 = 40%.
What is the bookmaker margin?
The amount by which the implied probabilities of all outcomes add up to more than 100%. If home, draw and away imply 104% in total, the margin (overround) is 4%.
How do you remove the margin?
The simplest method divides each implied probability by their total, so the three probabilities add up to exactly 100%. This site uses that proportional method for each bookmaker.
More guides
Probabilities are not guarantees and nothing here is betting advice. Responsible gambling.