Payroll tax. Payroll taxes are taxes imposed on employers or employees, and are usually calculated as a percentage of the salaries that employers pay their staff. Payroll taxes generally fall into two categories: deductions from an employee’s wages, and taxes paid by the employer based on the employee's wages. The first kind are taxes that employers are required to withhold from employees' wages, also known as withholding tax, pay-as-you-earn tax, or pay-as-you-go tax and often covering advance payment ...