How calculate income taxes in payroll?

Welcome to the Community, team9.

Allow me to provide information about how QuickBooks calculates payroll income taxes. The Federal income tax amount calculations are determined by the following factors:

• Employee's marital status
• the number of withholding allowances
• pay frequency
• projected annual income

You can check Payroll 101 that contain the break down of processing payroll and answers to frequently asked questions for your reference.

Let me know if you have any other concerns. I'm always here to help.