Margin / Overround Calculator
Paste the odds for a 2- or 3-way market to see the bookmaker margin. Anything under 4% is sharp; over 8% is poor value.
How it works
Implied probability of any decimal odds is 1 / odds. In a fair market, all outcomes' implied probabilities sum to 100%. Anything above 100% is the bookmaker's edge:
margin % = (sum of 1/odds − 1) × 100
For comparison: Pinnacle and Betfair Exchange typically run 2–4% on football 1X2; high-street bookies often run 6–10%.
Frequently asked questions
What is a bookmaker margin?
The margin (also called overround or vig) is how far the implied probabilities of all outcomes add up above 100%. A 1X2 market priced 2.00 / 3.40 / 3.80 implies 50% + 29.4% + 26.3% = 105.7%, a margin of 5.7%.
What counts as a good margin?
Below about 4% is competitive and typical of sharp bookmakers and exchange prices. Between 5% and 8% is common on main football markets, and anything higher means you pay a lot for every bet.
Is the margin spread evenly across outcomes?
Not always. Many bookmakers load more margin onto longshots than onto favourites (the favourite-longshot bias). The calculator shows the total margin, not how it is distributed.