FICA is the combined payroll tax withheld from every paycheck: 6.2% for Social Security (up to an annual wage base) and 1.45% for Medicare (with no cap, plus an extra 0.9% on high earners). Employers match the Social Security and Medicare portions.
Unlike federal income tax, FICA isn't reduced by the standard deduction or most pre-tax benefits beyond a few exceptions, and it isn't lowered by traditional 401(k) contributions. It's charged on your wages from the first dollar.
Related terms: Amortization · Traditional IRA