What Is FICA? The Paycheck Tax Nobody Explains
Social Security and Medicare taxes take a fixed slice of nearly every paycheck before income tax even starts. Who pays what, what the wage base means, and why the self-employed pay both halves.
Published · Taxes · 2 min read
Look at any pay stub and two deductions appear before income tax gets involved: Social Security and Medicare, together known as FICA — the Federal Insurance Contributions Act. For many workers, especially early in a career, FICA takes more than federal income tax does. It deserves five minutes of understanding.
The two pieces
Social Security is 6.2% of your wages, matched by another 6.2% from your employer. It funds retirement, disability, and survivor benefits. Crucially, it applies only up to an annual wage base — a ceiling adjusted each year. Wages above the ceiling pay no Social Security tax, which is why high earners see this line stop partway through the year.
Medicare is 1.45% from you and 1.45% from your employer, with no ceiling at all. Above a threshold, an Additional Medicare Tax of 0.9% applies to the employee side only — the employer does not match it.
The half you never see
Your employer's matching 7.65% never appears on your stub, but economists broadly treat it as part of your compensation — money your employer budgets for your position that you receive as future benefits rather than cash. When you compare employment to self-employment, this hidden half becomes very visible: the self-employed pay both sides, roughly 15.3%, as self-employment tax, partially offset by a deduction.
Why FICA feels different from income tax
- It is flat, then regressive. Everyone pays the same rate from the first dollar — there is no standard deduction, no brackets. And because Social Security stops at the wage base, the combined FICA rate actually falls for very high earners.
- Pre-tax benefits reduce it. Employer health premiums and FSA contributions typically escape FICA, while 401(k) contributions do not — they dodge income tax but still pay FICA.
- It is tied to benefits. Your Social Security retirement benefit is computed from the earnings you paid the tax on, so the line item is closer to a compulsory pension contribution than a pure tax.
To see the whole picture — both halves, the wage base cutoff, and the additional Medicare threshold — the payroll tax calculator splits every piece between employee and employer, and the take-home pay calculator shows where FICA sits alongside income tax on a real paycheck.
Run your own numbers
More on taxes
- Getting Your W-4 Right: Withholding Without the Guesswork
- Standard vs. Itemized Deductions: How to Know Which Side You Are On
- A Big Tax Refund Is Not a Bonus — It Is a Receipt for an Interest-Free Loan
This article is general education, not tax, legal, investment, or financial advice. Figures used in examples are illustrations, not quotes or predictions. For decisions that depend on your full situation, talk to a qualified professional.