Set trigger to win £x amount when placing back bet?

Hi
in the amount field use:
target profit / (back price -1)
e.g. 10/(back_price -1)

if you want to take into account commission:
(10/(1-commission))/(back_price-1)

Hi
The market variable "commission" returns your Betfair account commission rate divided by 100.
(10/(1-0.025))/(4.0-1) = 3.42

Hi
Betfair commission rate varies according to country, discount package etc. The software has a built-in variable to detect your commission rate linked to your Betfair username. In your case it is 2.5% and the variable will return 0.025.

if you copy this formula:
(10/(1-commission))/(back_price-1)and paste it into the amount field in the backing trigger, it will automatically bet the correct amount to return 10.00 after commission.

Please see attached screenshots on a historical market showing statement after commission. In this example the commission rate is 5%    

OK, I have come back to look at this again and realised that the discussion is based on a back bet.  Oops.

I wanted it to calculate a lay bet amout to;
1. Return 10.00 after 2.5% commission on win bets
2. To place lay bets after a loss where the amount is the lay_size + last_lost with a stake adjustment to still generate 10.00 on the next winning bet

The problem occurs when there have been a string of losing bets as, when you finally get a winning bet, the commission is now larger (on the inflated winning amount) that you get less than the target 10.00.

Hope that makes sense.  I could probably just add 0.50 after each loser perhaps ...

To place lay bets after a loss where the amount is the lay_size + last_lost with a stake adjustment to still generate 10.00 on the next winning bet

Hi
For lay bet with last_lost to return 10.00 after commission use:
(10+last_lost)/(1-commission)
Please test in test mode.