Book arbitrage - back all selections for a guaranteed profit

You can win a risk-free profit by backing all the selections in an event whenever its book percentage is less than 100% (underround book). Arb Cruncher calculates how much you should stake on each selection to ensure that you win the same net profit whichever selection wins. The book percentage is displayed in the Book box.
Open the Multiback calculator

Example 1
This is an example of a 98.38% book on a football match. The home team is best-priced at 1.82 with a bookmaker that has imposed a max stake limit of £250, and the draw is available to be backed at 3.70 on Betfair, where your commission is 5%. You would like to know how much to stake on the draw and the away team in order to win the same amount, whatever the result.

The respective stakes of £127.63 and £70.00 output by Multiback guarantee a profit of £7.37, whatever the result. This represents a return of 1.65% on your total stake of £447.63.

Note that the book percentage would be even lower (97.36%) if you didn't have to pay commission on the draw. Multiback factors the commission into its book percentage calculations when commission is payable on some but not all selections.

Example 2
This example is taken from a 95.4% book in a tennis match. There is plenty of money available to back the favourite (A) at 1.93 on Betfair, where your commission is 4.75%, and there is no max stake limit on the other player (B). You want to spend a total of £1,000 on this arb.

The stakes output by Multiback guarantee a profit of £48.22 whichever player wins. Whenever you are arbing on tennis matches, you should always check that both bookies have the same rules regarding settlement of uncompleted matches.