How to verify your PCB Calculations February 15, 2018 By kbadmin You are here: KB Home PCB Calculations How to verify your PCB Calculations < BackActpay has a unique feature that allows the PCB calculations using the online PCB calculator. Go to the PCB Online Screen. Click PCB Online followed by Set values. This will insert the relevant information from the payroll software into the PCB Online calculator. Click Submit to get the results.