Is there a reason why FIT payroll tax is different for each employee when they have the same gross pay and filing status?

Yes, @mthollyboro. I'd like to provide some information on how FIT payroll tax is determined.

Using the data from an employee's completed W-4 and the number of pay periods in a year, the Federal Income Tax (FIT) is computed. This yearly wage is then multiplied by the number of taxable gross wages. Deducting the amount of the allowed allowances.

I'll also attach these helpful modules to understand more about payroll types and how to handle year-end payroll works:

• Understand supported pay types and deductions in QuickBooks Online Payroll
• Year-end checklist for QuickBooks Online Payroll

Fill me in if you need anything else about payroll taxes or QuickBooks in particular. It's my pleasure to be of help always. Have a great week ahead!