For a 2-player game, for example, where the odds for player A winning are ‘a’ and the odds for player B winning are ‘b’, the margin will be given by:įor more extensive information, go to How do I calculate betting margins? For a fair book, this sum will always be 100%, since it is a reflection of the sum of the probabilities of all possible outcomes. He does this by shortening the odds relative to the fair expectation associated with each outcome.
Every bookmaker applies a margin to his betting odds to ensure that he can make a profit.
