[header] How to calculate payroll taxes [title] Have each worker complete a w-4. [step] The top portion of the w-4 form includes a personal allowance worksheet. As an employee, you enter information about yourself and your spouse, if applicable. 
If you have children, you may also enter withholding information for each child. [substeps] Assume that you and your spouse both work, and that you have three children who live at home with you.