Margin Calculator
Calculate bookmaker margin, implied probability, and fair odds in seconds. Useful for two-way markets, 1X2 football pricing, and any custom multi-outcome book.
| Outcome | Odds | Implied probability | Fair probability | Fair odds |
|---|---|---|---|---|
| Outcome 1 | 1.91 | 52.36% | 50.00% | 2 |
| Outcome 2 | 1.91 | 52.36% | 50.00% | 2 |
The calculator converts each decimal odd into implied probability using 1 / odds.
All implied probabilities are added together to get the book percentage. Anything above 100% is the bookmaker margin.
Fair odds are calculated by normalizing those implied probabilities back to a true 100% market.
What is bookmaker margin?
Bookmaker margin is the built-in edge added to a market so the total implied probability comes out above 100%. That extra percentage is what gives the bookmaker room to make money across the book.
This calculator helps you see how expensive a market really is. Lower margin usually means sharper pricing and better value for bettors, while higher margin means you are paying more hidden cost in the odds.
It is especially useful when comparing sportsbooks, checking two-way and 1X2 markets, or stripping out the overround to estimate fair odds and fair probability for each outcome.