OASDI on your paycheck stands for Old-Age, Survivors, and Disability Insurance, which is the formal name for Social Security. The line represents 6.2% of your gross wages going to the federal program that pays retirement, survivor, and disability benefits, and your employer pays a matching 6.2% you never see.1Social Security Administration. Social Security and Medicare Tax Rates In 2026, the tax applies only to the first $184,500 you earn; once your year-to-date pay crosses that ceiling, the deduction stops for the rest of the year.2Social Security Administration. Contribution and Benefit Base
What Your OASDI Money Pays For
The Social Security Administration uses OASDI collections to fund three kinds of benefits. The largest share pays monthly retirement checks to workers who paid in long enough to qualify. A second portion pays survivor benefits to spouses and children of workers who die. The third funds disability payments for people with medical conditions severe enough to prevent work for at least 12 consecutive months.3Social Security Administration. Disability Benefits – How Does Someone Become Eligible
The amount you eventually collect is tied to what you contributed while working, so the deduction is not just a tax. It builds your own future eligibility.
Why Your Stub Might Say FICA Instead
Some pay stubs label the same deduction “FICA,” “SS Tax,” or “OASDI/EE” (the “EE” meaning employee share). FICA is the Federal Insurance Contributions Act, the law that authorizes both Social Security and Medicare payroll taxes.4Office of the Law Revision Counsel. 26 USC Ch. 21 – Federal Insurance Contributions Act OASDI is one half of FICA. The other half is the Medicare Hospital Insurance tax at 1.45%. Together they produce the 7.65% total FICA rate on each side of the payroll.1Social Security Administration. Social Security and Medicare Tax Rates
If your stub shows a single FICA line, it likely combines both. If it shows two lines, one will be the 6.2% OASDI piece and the other the 1.45% Medicare piece.
The 2026 Rate and Wage Cap
The 6.2% employee rate is set by statute and has not changed since 1990. Congress adjusts it only by legislation, so it does not move with inflation the way income tax brackets do.1Social Security Administration. Social Security and Medicare Tax Rates
What does change each year is the wage cap. For 2026 the cap is $184,500, meaning the maximum OASDI a worker can pay in one year is $11,439. Your employer pays the same amount.2Social Security Administration. Contribution and Benefit Base Medicare has no equivalent ceiling; the 1.45% continues on every dollar you earn, so if you cross the cap mid-year you will see the OASDI deduction disappear while the Medicare line remains.
If you are self-employed, you pay both halves through the Self-Employment Contributions Act: the full 12.4% OASDI plus the full 2.9% Medicare, for 15.3% total, reported on Schedule SE.5Internal Revenue Service. Self-employment Tax (Social Security and Medicare Taxes) You can deduct half of that self-employment tax when calculating adjusted gross income.6Internal Revenue Service. Topic No. 554, Self-employment Tax
Which Paycheck Items Are Subject to OASDI
Not every pre-tax deduction reduces your OASDI. Traditional and Roth 401(k) contributions lower your federal income tax withholding but remain fully subject to OASDI and Medicare. The IRS treats elective 401(k) deferrals as wages for FICA even though they are excluded from current income tax.7Internal Revenue Service. Participants 401(k) Plan Overview
Health savings account and flexible spending account contributions routed through an employer’s cafeteria plan are different. Those deductions are exempt from both income tax and FICA, so they actually reduce the wages on which your 6.2% is calculated. The trade-off is that lower recorded earnings can slightly reduce your future Social Security benefit. For most workers the current tax savings outweigh that effect, but the connection is real.
What Your Contributions Buy You
Every dollar of OASDI you pay earns credits toward future eligibility. In 2026, you earn one credit for every $1,890 in covered earnings, up to four credits per year.8Social Security Administration. Quarter of Coverage Earning $7,560 in a year maxes out your credits regardless of how much more you make.9Social Security Administration. Social Security Credits and Benefit Eligibility
Retirement benefits require 40 credits, or roughly 10 years of covered work. Disability benefits use a lower threshold that varies with the age at which the disability begins.10Social Security Administration. How You Earn Credits Falling one credit short means no benefit, so the earnings record behind your OASDI deductions is worth checking periodically.
Who Can Be Exempt From OASDI
Most workers cannot opt out. A few narrow categories are legally exempt:
- Foreign students on F-1, J-1, or M-1 visas who have been in the U.S. fewer than five calendar years, on wages earned under the terms of the visa. The exemption ends once they become resident aliens.11Internal Revenue Service. Foreign Student Liability for Social Security and Medicare Taxes
- Students working for the same school where they are enrolled at least half-time, if the work is incidental to their studies and they are not treated as professional employees receiving benefits like retirement plan participation or paid leave.12Internal Revenue Service. Student FICA Exception
- Members of a recognized religious sect that has provided for its members since before 1951 and is conscientiously opposed to insurance benefits, who file Form 4029 and waive all rights to future Social Security and Medicare benefits.13Internal Revenue Service. Form 4029, Application for Exemption From Social Security and Medicare Taxes and Waiver of Benefits
- Certain state and local government workers covered by a qualifying government pension whose positions are not covered by a Section 218 agreement with the Social Security Administration.14Social Security Administration. Section 218 Agreements
If none of these applies, OASDI withholding is mandatory and your employer has no discretion to skip it.
When Two Employers Withhold Too Much
Each employer withholds OASDI without knowing what any other employer has already withheld. If you hold more than one job and your combined wages exceed $184,500, you will overpay Social Security tax during the year.15Social Security Administration. Social Security Tax Limits on Your Earnings
You recover the excess when you file your return, claiming it as a credit against your income tax. Spouses filing jointly must figure the excess separately.16Internal Revenue Service. Topic No. 608, Excess Social Security and RRTA Tax Withheld If a single employer over-withheld, ask that employer to correct it first; if they will not, file Form 843 with a copy of your W-2 to claim the refund directly from the IRS.17Internal Revenue Service. Instructions for Form 843 – Claim for Refund and Request for Abatement