Overround Calculator

Calculate bookmaker margin, overround, and market percentage from decimal odds.

Bet sides
Margin check
11.90  +  11.90  =  105.26%\dfrac{\normalsize 1}{\normalsize 1.90} \; {\normalsize +} \; \dfrac{\normalsize 1}{\normalsize 1.90} \; {\normalsize =} \; {\normalsize 105.26\%}
This market includes bookmaker margin: the combined implied probability is above 100%.
Margin summary
Market percentage105.26%
Bookmaker margin5.26%

Frequently Asked Questions

What is overround in betting?+

Overround is the amount by which a market's combined implied probabilities exceed 100%. It represents the bookmaker's built-in margin across all outcomes. Read the bookmaker overround guide.

How do you calculate bookmaker margin?+

Convert each outcome's odds into implied probability, add them together, then subtract 100%. For decimal odds, implied probability is calculated as 1 / decimal odds.

Is a lower bookmaker margin better?+

Usually, yes. A lower margin means the market is priced closer to fair value, reducing the built-in disadvantage for bettors.