What should my max CPC be?

If your website needs on average 10 people to view before one calls you, the CPA target is £20 and the Conversion rate = 1/10 = 0.1 = 10%. The Ideal Max CPC = 20 x 0.1 x 1.2 = $0.24.

For More Information Please Refer: https://www.hallaminternet.com/how-calculate-ideal-maximum-cpc-adwords/