Generally, all of an employee's earnings which are less than $118,500 in the calendar year 2015 are subject to payroll withholdings of 6.2% for the Social Security tax plus 1.45% for the Medicare tax. In addition, the employer is required to pay a similar amount. The result is that the employer must remit 15.3% (6.2% + 6.2% + 1.45% + 1.45%) of each employee's wages or salaries that are less than $118,500 in 2015. (The earnings base and the rates for other years and any surcharges can be found on IRS.gov.)
A self-employed person must pay both the employee portion and the employer portion of the FICA tax.
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