The Multi Promo calculator is designed to help you secure a profit from multi promos that offer a refund if one leg fails, or from multi boosts.

In order to minimise risk, it uses a sequential lay approach (ie you wait for game 1 to finish before laying game 2 etc).

The calc will work out the ideal lay stake for each step of the process. For each winning leg, the subsequent lay stake will increase to cover the lost Betfair liability. This can lead to high commission costs, so profits are lower with this method than they are with the no-lay or lay-at-the-start approaches.

You should also be aware that for sequential lays to work you cannot select games that overlap. There needs to be time to place your lays between the games.

Using the Calc

The calculator is split into 4 sections:

• Bookie – For entering your multi stake and odds
• Betfair – For entering your commission rate and the method you wish to use (more on that later)
• Bonus – For listing the bonus, if applicable, and the retention rate you expect (cash bonuses would be 100%)
• Lays – This is where the maths happens. I’ll go into more detail below.

Let’s imagine we are placing a four leg multi with a promo that returns a $50 bonus bet if one leg loses. The first step is to enter all of the info that we know. We take the lay odds from Betfair.

The calc then provides a suggested lay for each leg. Depending on your preference you can either follow the suggestion or lay a different amount.

Once you enter your actual lay amount, the calc will then adjust its suggestion for the next selection:

If your first selection wins you then have to lay the second selection. Again, you can decide whether to follow the calc or make your own adjustments

When you reach the final selection, the suggested lay will be different depending on whether you have chosen the ‘Lock-in’ method or the ‘No-loss’ method. The image above shows the ‘Lock-in’ method and you can see that our P/L figure is the same no matter what happens on the final selection.

If we were to change it to ‘No-loss’ it would look like this:

In this scenario we break-even if the final selection loses, but have a bigger profit if it wins.

At each stage of the process, the final column shows what your p/l would be if that selection loses. If you follow the suggested lay amounts it should always be break-even up until the final selection.

If you are using an odds boost promo instead of a refund the ‘bonus’ section should be left at 0.00. If it is a good enough boost it should create an arb that lets you lock-in without needing any bonus.

Please be aware that there is some risk to these promos. Odds can move between the time you place the bet and the time that you are actually ready to lay a selection. That can go for you or against you, so you have to be willing to accept a loss in some cases.