Calculating a PPC Cost Per Conversion goal is essential, and it should come from the client’s profit calculation. A calculation I go by is as follows:
Customer lifetime value/Close rate=Cost per Conversion benchmark.

So as a hypothetical if a client’s customer lifetime value is $400 and for every 10 calls, they turn 1 into a client (close rate) 400/10=40. The cost per conversion goal should be 40 as a max.
Here is a simple easy calculator to help with this equation.

Try Out This Awesome Profit Calculator From RothmanPPC.

Google Ads Profit Calculator