Straight answer
What do Social Security taxes pay for?
The Social Security line on your pay stub buys three insurance policies at once: retirement income for you and your family, survivor benefits if you die while people depend on your income, and disability coverage if you can no longer work. Roughly 85 cents of each dollar funds retirement and survivor benefits, about 15 cents funds disability benefits, and less than a penny runs the whole operation.
What is FICA, exactly?
The Federal Insurance Contributions Act — the law behind the deduction. It bundles two separate taxes: Social Security (6.2% of your wages up to an annually adjusted cap, matched by your employer, so 12.4% total) and Medicare (1.45% with no cap, also matched). Self-employed? You pay both halves yourself. The two programs have separate trust funds; your Social Security tax does not fund Medicare.
Where does the money actually sit?
It mostly doesn't sit — Social Security is pay-as-you-go, so today's workers largely fund today's beneficiaries. Surpluses go into trust funds invested in special-issue Treasury securities, meaning the government borrows from the fund and owes it back with interest. There is no personal account with your name on it; what you accrue is a claim on a benefit formula built from your earnings record.
Will it be there when I retire?
In some form, almost certainly — but possibly not in full. The trustees project the trust fund reserves run short in the mid-2030s without congressional action; at that point incoming payroll taxes would still cover the large majority of scheduled benefits, but not all of them. The practical takeaway isn't panic, it's design: Social Security was built to replace only around 40% of a typical worker's pre-retirement income. The other 60% was always your job — which is what the retirement match and your own savings rate are for.
How is my benefit calculated?
You qualify with 40 work credits — roughly ten working years. The formula averages your highest-earning 35 years (adjusted for wage growth) into a monthly figure, then applies a progressive formula that replaces a larger share of income for lower earners. When you claim matters enormously: claiming at 62 permanently reduces your check to about 70% of your full amount, while each year you wait past full retirement age adds roughly 8%, topping out at age 70.
- Social Security Administration — Understanding the Benefits
- SSA Board of Trustees annual report
- CBPP — Policy Basics: Federal Payroll Taxes
Money Mechanics explains how things work in plain language. It is not personalized financial advice.