OASDI withholding on your paycheck is the Social Security tax. It stands for Old-Age, Survivors, and Disability Insurance, and in 2026 your employer takes 6.2% of your gross wages on every check until your year-to-date earnings reach $184,500.1Social Security Administration. Contribution and Benefit Base Some pay stubs print “OASDI,” others use “Social Security” or “FICA-SS.” Same deduction, same money, same destination: the Social Security Trust Funds that pay current retirees, surviving family members of workers who have died, and people receiving disability benefits.
What the Three Letters Cover
The program name spells out what your contribution funds. Old-Age benefits go to retirees. Survivors benefits go to the spouse, children, or other dependents of a worker who dies. Disability Insurance covers workers whose condition is severe enough to keep them from earning a living.
Social Security is pay-as-you-go. Your withholding is not sitting in an account with your name on it; it is paying this month’s beneficiaries. In return, you build credits toward your own eligibility for retirement, survivors, or disability benefits later.
How Much Comes Out of Your Check
The employee rate is 6.2% of your gross taxable wages. Your employer pays a matching 6.2% that you never see on the stub, bringing the combined rate to 12.4%.2Internal Revenue Service. Topic No. 751, Social Security and Medicare Withholding Rates The rate is set by federal law. Your W-4 elections, filing status, and allowances have no effect on it.3Social Security Administration. FICA and SECA Tax Rates
One thing to know if you contribute to a 401(k) or 403(b): those pre-tax deferrals lower your federal income tax withholding but not your OASDI wages. Social Security tax is calculated on your gross pay before the retirement deferral comes out.4Internal Revenue Service. Retirement Plan FAQs Regarding Contributions Earn $5,000 in a pay period, defer $500 to your 401(k), and OASDI still comes out on the full $5,000.
The 2026 Wage Base Cap
OASDI applies only to a fixed amount of earnings each year. For 2026 the ceiling is $184,500.1Social Security Administration. Contribution and Benefit Base Once your year-to-date gross wages cross that line, your employer stops withholding the 6.2% and your take-home pay rises for the rest of the year. Withholding resets on January 1.
The most an employee can pay in OASDI for 2026 is $11,439, and the employer pays the same $11,439. The Social Security Administration adjusts the wage base each year based on the national average wage index, so it tends to climb. The 2025 limit was $176,100.5Social Security Administration. 2025 Cost-of-Living Adjustment (COLA) Fact Sheet
If You Work Two Jobs
Each employer tracks the wage base independently. Work two jobs with combined earnings above $184,500, and both will keep withholding OASDI on their own payroll, which can push your total past the $11,439 cap. Your employers are not required to refund the excess. You claim it back as a credit on your federal income tax return, using the instructions for excess Social Security tax withheld.6Internal Revenue Service. Topic No. 608, Excess Social Security and RRTA Tax Withheld
OASDI Versus the Medicare Line
Your stub almost certainly shows a second FICA deduction for Medicare, sometimes labeled “HI” for Hospital Insurance. Medicare’s employee rate is 1.45%, matched by the employer.2Internal Revenue Service. Topic No. 751, Social Security and Medicare Withholding Rates OASDI plus Medicare comes to 7.65% of covered wages, which is the full employee-side FICA number.
The difference that matters: Medicare has no wage base cap. OASDI stops at $184,500; Medicare’s 1.45% keeps coming out of every dollar you earn. Once your wages pass $200,000 in a calendar year, your employer must also withhold an additional 0.9% Medicare surtax, regardless of your filing status. The employer does not match that 0.9%.7Internal Revenue Service. Topic No. 560, Additional Medicare Tax
Who Doesn’t Pay OASDI
Most workers pay it with no way around it. A few narrow categories are exempt, and if none of them describe you, the deduction on your stub is correct.
- Students employed by the school where they are enrolled at least half-time are generally exempt from FICA on that job. The exemption is lost if the position is a professional one carrying benefits like paid vacation, holidays, or retirement plan participation.8Internal Revenue Service. Student FICA Exception
- Members of recognized religious groups that have provided for their dependents since at least December 31, 1950, and that conscientiously object to insurance benefits, can apply for exemption on IRS Form 4029. Old Order Amish and some Mennonite congregations are the usual examples. Filing the form permanently waives all Social Security and Medicare benefits.9Internal Revenue Service. Form 4029, Application for Exemption From Social Security and Medicare Taxes and Waiver of Benefits
- Nonresident alien students in F-1, J-1, or M-1 status are generally exempt from FICA during their first five calendar years in the U.S.10Internal Revenue Service. Foreign Student Liability for Social Security and Medicare Taxes
- Some state and local government workers covered by a qualifying public retirement system, and not brought under a Section 218 agreement, can be exempt. This most often affects certain police officers, firefighters, and people in temporary or fee-basis positions.11Social Security Administration. Social Security Act 218 – Voluntary Agreements for Coverage of State and Local Employees
What You Get for Paying It
Every year of OASDI-taxed work earns you Social Security credits, formally called Quarters of Coverage. In 2026, one credit takes $1,890 in covered earnings, and you can earn up to four per year, so wages of at least $7,560 during the year get you the full four.12Social Security Administration. Quarter of Coverage You need 40 credits, roughly ten years of work, to qualify for retirement benefits.13Social Security Administration. Social Security Credits and Benefit Eligibility
Your monthly benefit is based on your highest 35 years of OASDI-taxed earnings, indexed for wage inflation. Higher taxed earnings mean a bigger benefit, but only up to each year’s wage base; anything above the cap was never taxed and does not count. Full retirement age is 67 for anyone born in 1960 or later, with reductions for claiming earlier and increases for waiting until 70.14Social Security Administration. Retirement Age and Benefit Reduction Once you are collecting, an annual cost-of-living adjustment keeps the check in line with inflation; for 2026 that COLA was 2.8%.15Social Security Administration. 2026 Cost-of-Living Adjustment (COLA) Fact Sheet