2018 Annual Earnings Limit for Social Security Payroll Tax
The maximum amount of an employee's 2018 earnings (and a self-employed person's net income) that is subject to the Social Security payroll tax is $128,400. This amount is also known as the Social Security annual limit, wage base, contribution and benefit base, ceiling, tax cap, and maximum taxable earnings. The maximum amount is adjusted annually based on the national average wage index.
2019 Annual Earnings Limit for Social Security Payroll Tax
For the calendar year 2019 (January 1 through December 31, 2019) the maximum amount of an employee's earnings that is subject to the Social Security payroll tax is $132,900.
An Employer Must Match Its Employees' Social Security Payroll Taxes
The earnings limits are used to compute the employee's maximum Social Security tax and therefore the employer's maximum Social Security payroll tax for each employee. (The employer is required to match each employee's withholdings of the Social Security tax and must remit both the employees' withholdings and the employer's matching amount to the U.S. government.)
Social Security Payroll Tax is One Part of the FICA Payroll Tax
The combination of the Social Security payroll tax and the Medicare payroll tax is referred to as the FICA tax. However, there is no annual limit or cap on the earnings when computing the Medicare tax for the employee, the self-employed person, or the employer.