What FICA stands for
FICA stands for the Federal Insurance Contributions Act, the 1935 law that established Social Security and (in 1965) added Medicare. On a paystub, "FICA" is often broken into two separate lines: "Social Security Tax" or "OASDI" (6.2%) and "Medicare Tax" (1.45%).
It is a payroll tax, not an income tax — it applies to wages, salaries, and tips, and it is calculated on gross earnings before most deductions. FICA is flat: everyone pays the same percentage on the first dollar of wages regardless of filing status or income (with one adjustment for high earners on Medicare).
2025 rates and wage base
• Social Security: 6.2% of the first $176,100 of wages. Once you hit the wage base, Social Security tax stops for the rest of the calendar year.
• Medicare: 1.45% on all wages, no cap.
• Additional Medicare Tax: 0.9% on wages above $200,000 (single) or $250,000 (married filing jointly). This is employee-only — employers do not match it.
• Employer match: Employers pay the same 6.2% + 1.45% = 7.65% on your behalf. That means each dollar you earn generates $0.153 in FICA revenue.
FICA on your paystub
A US paystub typically shows two FICA lines: "OASDI" (Old Age, Survivors, and Disability Insurance — the formal name for Social Security) at 6.2%, and "Medicare" at 1.45%. Some employers combine them into a single "FICA" line at 7.65%.
YTD OASDI stops incrementing once you hit the wage base. If you switch jobs mid-year, the new employer restarts your OASDI at $0 — the wage base is per-employer, not per-person. That can mean overpaying Social Security; you claim it back on your Form 1040 (line 11 of Schedule 3).
Self-employed: SECA
Self-employed workers pay both the employee and employer halves through the Self-Employment Contributions Act (SECA) — 12.4% for Social Security + 2.9% for Medicare = 15.3% total. It is paid quarterly through estimated tax payments and reconciled on Schedule SE with your Form 1040.
You do get to deduct half of the SECA tax on your income tax return as an above-the-line deduction, which mirrors the fact that employers deduct their FICA match as a business expense.