Guide

FICA explained: Social Security and Medicare

FICA is the Federal Insurance Contributions Act. On an employee stub it is usually two lines (sometimes three): Social Security, Medicare, and occasionally Additional Medicare Tax.

The employee rates

• Social Security (OASDI): 6.2% of wages up to the annual wage base — $176,100 in 2025 and $184,500 in 2026.
• Medicare (HI): 1.45% of all covered wages. No cap.
• Additional Medicare: 0.9% above a filing-status threshold ($200,000 single / $250,000 joint / $125,000 separate). Employers start withholding it at $200,000 of wages from that job.

Your employer matches 6.2% + 1.45%. They do not match Additional Medicare. Self-employed people pay both halves through SECA, which this employee calculator does not model.

Why high earners see Social Security “disappear”

Once wages pass the wage base, OASDI withholding stops for the rest of the calendar year. A November raise can look like a mysterious take-home bump. Medicare continues.

401(k) does not usually help FICA

Traditional 401(k) elective deferrals generally remain Social Security and Medicare wages. That surprises people who watch only the federal income-tax line fall. Health premiums under a section 125 plan often do reduce FICA; we do not model those yet.

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