Implied Probability & Margin Calculator
By the TheyShoot editorial team. Updated
Implied probability is 1 ÷ decimal odds: odds of 2.50 imply a 40% chance. Enter the odds for every outcome in a market to see each implied probability and the bookmaker's margin, the amount by which the probabilities add up to more than 100%.
Bookmaker margin (overround)
4.8%
The odds add up to a 104.8% book. Fair probabilities remove the margin proportionally.
How to use the calculator
- Enter the odds for every possible outcome, for example home, draw and away.
- Read each outcome's implied probability, and its fair probability with the margin removed.
- Check the margin: the lower it is, the better value the market gives you overall.
How the margin is worked out
Add up the implied probabilities of all outcomes. For home 2.10, draw 3.40 and away 3.60, that's 47.6% + 29.4% + 27.8% = 104.8%, so the margin is 4.8%. Dividing each implied probability by 104.8% gives the fair probabilities, which add up to exactly 100%.
Compare fair probabilities with our model's probabilities: when our number is higher than the market's fair probability, the price may be value.
FAQs
What is implied probability?
The chance of an outcome that the odds suggest: 1 divided by the decimal odds. Odds of 4.00 imply 25%.
What is a bookmaker's margin?
How far the implied probabilities of every outcome add up above 100%. A 105% book has a 5% margin.