Overview: Understanding what Social Security does and how it pays for itself provides the foundation for every other topic in this chapter.

Social Security was created by the Social Security Act of 1935, born directly from the economic devastation of the Great Depression. Congress recognized that individual saving alone was insufficient to protect workers from the financial catastrophe of retirement poverty, disability, or premature death. The system was designed as social insurance — workers contribute during their productive years, and the program pays them back (and their families) when a life event interrupts their earning power.

The program's full acronym is OASDI, standing for Old-Age, Survivors, and Disability Insurance. This label neatly summarizes the three branches of coverage the system provides. A separate program, Supplemental Security Income (SSI), is administered by the Social Security Administration but funded from general Treasury revenues rather than payroll taxes — SSI is a needs-based welfare program, not a social insurance program, and candidates should not confuse the two.

How FICA Funds the System

Social Security is funded through the Federal Insurance Contributions Act (FICA) payroll tax. Both employees and employers pay equal shares: 6.2% each, for a combined rate of 12.4%, on wages up to the annual taxable wage base — $184,500 in 2026. Once a worker's earnings for the year cross that ceiling, neither worker nor employer owes additional Social Security tax on further earnings. (Medicare is funded by a separate FICA component of 1.45% each, bringing the total FICA rate to 7.65% per side.)

Self-employed workers bear both halves under the Self-Employment Contributions Act (SECA), paying 12.4% on their net self-employment income, though they may deduct the employer-equivalent half from their federal taxable income.

Social Security is a pay-as-you-go system. Taxes collected from today's workers are used to pay today's beneficiaries. Surpluses flow into the Old-Age and Survivors Insurance (OASI) Trust Fund and the Disability Insurance (DI) Trust Fund, invested in special-issue U.S. Treasury securities.

FAQ

Does Social Security track my individual contributions in a personal account?
No. Social Security is not a savings account. Your FICA taxes pay current beneficiaries, and future workers' taxes will pay your benefits. Your benefit amount is calculated from your wage history, not from the taxes you personally paid.

Is SSI the same as SSDI?
No. SSDI (Social Security Disability Insurance) is funded by FICA taxes and earned through work credits. SSI (Supplemental Security Income) is a needs-based welfare program funded by general tax revenues, with no work-credit requirement. A person can receive both if they meet the eligibility requirements for each.