For 2018, the maximum limit on earnings for withholding of Social Security (old-age, survivors, and disability insurance) tax is $128,700.00. The Social Security tax rate remains at 6.2 percent. The resulting maximum Social Security tax for 2018 is $7,979.40.
There is no limit on the amount of earnings subject to Medicare (hospital insurance) tax. The Medicare tax rate applies to all taxable wages and remains at 1.45 percent with the exception of an “additional Medicare tax” assessed against all taxable wages paid in excess of the applicable threshold (see Note). The FICA tax rate, which is the combined Social Security rate of 6.2 percent and the Medicare rate of 1.45 percent, remains 7.65 percent for 2018 (or 8.55 percent for taxable wages paid in excess of the applicable threshold).
The information in the following table shows the changes in Social Security withholding limits from 2017 to 2018. There are no changes in Medicare limits.
Note: The Patient Protection and Affordable Care Act signed into law March 23, 2010, created the “additional Medicare tax” that changed Medicare withholding computations effective January 1, 2013. All wages, self-employment income, and other compensation that are subject to regular Medicare tax and are paid in excess of the applicable threshold are subject to the additional Medicare tax. Employers are required to withhold the additional Medicare tax at a 0.9 percent rate on wages and other compensation paid to an employee in excess of $200,000 in a calendar year. There is no employer match for the additional Medicare tax.
— Payroll,
Controller, 11-23-17
