Every paycheck has more than just income tax taken out of it. FICA (Federal Insurance Contributions Act) tax is a separate, flat-rate payroll tax that funds Social Security and Medicare. Unlike income tax, FICA isn't affected by your deductions or filing status — it's calculated straight off your gross wages.
Social Security: 6.2%, up to a yearly cap
Social Security tax is 6.2% of your wages. But it only applies up to an annual limit called the wage cap — for 2026, that cap is $184,500. Once your year-to-date wages cross that number, Social Security tax stops being withheld for the rest of the year. This is why very high earners sometimes notice their paycheck get slightly bigger later in the year — the Social Security portion simply disappears once they've hit the cap.
Medicare: 1.45%, with no cap at all
Medicare tax is 1.45% of every dollar of wages, with no wage cap. Whether you earn $40,000 or $4 million, every dollar gets the same 1.45% Medicare tax.
The additional 0.9% Medicare surtax
High earners pay an extra 0.9% Medicare surtax on wages above a threshold that depends on filing status:
- Single or Head of Household: wages above $200,000
- Married Filing Jointly: wages above $250,000
- Married Filing Separately: wages above $125,000
This surtax only applies to the amount above the threshold, not your entire wages — the same slice-by-slice idea as income tax brackets.
A worked example
Take a Single filer earning $220,000 in wages for the year. Social Security only applies up to the $184,500 cap, so Social Security tax is $184,500 × 6.2% = $11,439. Medicare applies to the full $220,000, so base Medicare tax is $3,190. Since this filer's wages exceed the $200,000 threshold by $20,000, they also owe an additional Medicare surtax of $20,000 × 0.9% = $180. Total FICA tax for the year: $14,809.
Self-employed workers pay both halves
When you work for an employer, your employer pays a matching share of Social Security and Medicare on your behalf — you never see it, but it's there. If you're self-employed, there's no employer to split the cost with, so you pay both the employee and employer share yourself: 12.4% for Social Security plus 2.9% for Medicare, a combined 15.3% self-employment tax rate (still applied to the Social Security wage cap and Medicare surtax rules above). The good news is you get to deduct half of that self-employment tax when calculating your income tax, which softens the blow somewhat.