What Is OASDI Tax? Social Security Tax Explained Simply
Look at your pay stub and you’ll probably see a line labeled OASDI — or maybe “Fed OASDI/EE” or just “Social Security.” It’s one of the biggest deductions on your paycheck, yet most people have no idea what the letters mean or where the money actually goes.
OASDI is simply the official name for the Social Security tax. Every payday, you and your employer each chip in a percentage of your earnings to fund retirement, disability, and survivor benefits for millions of Americans. In this guide, you’ll learn exactly what OASDI stands for, how much you’re paying in 2026, why there’s a cap on it, and how it differs from the Medicare tax sitting right next to it on your pay stub.
Disclaimer: This article is for educational purposes only and is not tax or financial advice. Consult a qualified tax professional for your situation.
What Does OASDI Stand For?
OASDI stands for Old-Age, Survivors, and Disability Insurance. That’s the formal, legal name of the U.S. Social Security program. The three words describe the three types of benefits the program pays:
- Old-Age: Monthly retirement benefits paid to workers who have earned enough work credits and reached retirement age.
- Survivors: Benefits paid to the spouses, children, and sometimes parents of a worker who has died.
- Disability Insurance: Benefits (known as SSDI — Social Security Disability Insurance) paid to workers who can no longer work because of a serious medical condition.
So when your pay stub says “OASDI,” it means you’re paying into the insurance system that funds all three of these benefit types. It’s not a separate program from Social Security — it is Social Security, just under its official government name.
OASDI and Social Security: Are They the Same Thing?
Yes — OASDI and the Social Security tax are exactly the same thing. The terms are used interchangeably:
- The IRS and the Social Security Administration (SSA) call the program OASDI.
- Your employer, your pay stub software, and most people in everyday conversation call it Social Security tax.
- On pay stubs, you might see it labeled as OASDI, Fed OASDI/EE, SS, or Social Security — all of these refer to the same 6.2% deduction.
One thing OASDI is not: it is different from SSI (Supplemental Security Income). SSI is a separate, need-based program for people with limited income and resources — it isn’t funded by the OASDI payroll tax, and you don’t need a work history to qualify for it. Don’t mix the two up.
OASDI and FICA: How They Fit Together
OASDI is one half of FICA, the Federal Insurance Contributions Act — the federal law that requires payroll taxes to be withheld from your wages. FICA has exactly two parts:
- OASDI (Social Security) — funds retirement, survivor, and disability benefits.
- HI (Hospital Insurance / Medicare) — funds Medicare health coverage for people 65 and older and certain younger people with disabilities.
Your total FICA withholding is the sum of both parts. Here’s how they compare:
| OASDI (Social Security) | Medicare (HI) | |
|---|---|---|
| Employee rate | 6.2% | 1.45% |
| Employer rate | 6.2% | 1.45% |
| Total FICA rate (employee side) | 6.2% | 1.45% |
| Combined employee FICA | 7.65% | |
| Wage base limit | Yes — $184,500 in 2026 | No limit |
| Self-employed rate | 12.4% | 2.9% |
| Additional surtax | None | 0.9% on wages over $200,000 (single) / $250,000 (joint) |
| Where it goes | OASI and DI trust funds | Medicare Hospital Insurance trust fund |
The key difference to remember: OASDI has a cap, Medicare doesn’t. Once your earnings pass the annual wage base limit, OASDI withholding stops for the rest of the year — but Medicare tax keeps coming out of every dollar you earn, no matter how high your income goes.
The OASDI Tax Rate in 2026
The OASDI tax rate is 6.2% for employees and 6.2% for employers — a rate that hasn’t changed since 1990. Your employer matches your contribution dollar for dollar, so a combined 12.4% of your wages (up to the wage base) goes into the Social Security system.
Here’s what that looks like in practice:
- Earn $50,000 in 2026 → you pay $3,100 in OASDI tax; your employer pays another $3,100.
- Earn $100,000 in 2026 → you pay $6,200; your employer matches with $6,200.
- Earn $184,500 or more in 2026 → you pay the maximum, $11,439.00; your employer pays the same.
If you’re self-employed, there’s no employer to split the bill with — you pay the full 12.4% yourself (more on that below).
The Wage Base Limit (Taxable Maximum)
The wage base limit — also called the taxable maximum or contribution and benefit base — is the maximum amount of annual earnings subject to OASDI tax. In 2026, the wage base is $184,500, up from $176,100 in 2025.
What this means for you:
- If you earn less than $184,500 in 2026, OASDI tax comes out of your entire paycheck.
- If you earn more than $184,500, OASDI withholding stops once your year-to-date earnings hit the cap. You’ll notice your take-home pay jump slightly for the rest of the year.
- The cap resets every January 1.
The wage base rises most years to keep pace with average wage growth. Recent history:
| Year | Wage Base Limit | Max Employee OASDI Tax |
|---|---|---|
| 2024 | $168,600 | $10,453.20 |
| 2025 | $176,100 | $10,918.20 |
| 2026 | $184,500 | $11,439.00 |
One quirk worth knowing: the wage base limit applies per employer, not per person. If you work two jobs and earn $100,000 at each, both employers withhold OASDI on the full $100,000 — even though your combined $200,000 exceeds the cap. The good news: you can claim the excess back as a credit when you file your tax return.
Who Pays OASDI Tax?
Almost everyone who earns wages in the United States pays OASDI tax. That includes:
- Full-time and part-time employees — withheld automatically from each paycheck.
- Self-employed workers — paid through the self-employment tax (see below).
- Most government workers — though some state and local government employees covered by separate pension systems may be exempt.
A few groups generally don’t pay OASDI tax:
- Certain religious groups with conscientious objections (with approved exemption).
- Some student workers employed by their own university while enrolled.
- Nonresident aliens in specific visa categories (such as F-1 students during their first years).
For the vast majority of American workers, though, OASDI is simply a fact of payday — as automatic as the income tax withholding sitting above it. If you’re unsure how these payroll taxes interact with your annual return, our guide on when federal taxes are due walks through the key deadlines.
Self-Employed Workers and OASDI (SECA)
If you work for yourself — freelancer, contractor, gig worker, small business owner — there’s no employer to pay the matching 6.2%. Instead, you pay both halves through the Self-Employment Contributions Act (SECA):
- OASDI portion: 12.4% of net self-employment earnings (up to the $184,500 wage base).
- Medicare portion: 2.9% of all net self-employment earnings (no cap).
At the 2026 wage base, a self-employed person earning $184,500 or more pays a maximum of $22,878 in OASDI tax alone — double what an employee pays.
There is one consolation: you can deduct half of your self-employment tax as an above-the-line deduction on your Form 1040, which lowers your taxable income. And remember, deliberately hiding self-employment income to dodge this tax crosses the line into tax evasion — a federal crime with penalties that include prison time.
Where Does OASDI Tax Money Go?
Your OASDI taxes don’t go into a personal savings account with your name on it. They flow into two federal trust funds:
- The Old-Age and Survivors Insurance (OASI) Trust Fund — pays retirement and survivor benefits.
- The Disability Insurance (DI) Trust Fund — pays disability benefits.
Together these are often called the OASDI trust funds. The system works on a pay-as-you-go basis: today’s workers fund today’s beneficiaries. Your future benefits will be paid by the workers contributing after you.
Your benefit amount later in life is based on your lifetime earnings record — specifically, your highest 35 years of earnings (up to the wage base each year). That’s why the wage base is also called the “contribution and benefit base”: earnings above the cap aren’t taxed, but they also don’t count toward your benefit calculation.
Frequently Asked Questions
Is OASDI the same as Social Security tax?
Yes. OASDI (Old-Age, Survivors, and Disability Insurance) is the official name of the program most people call Social Security. On your pay stub, the labels “OASDI,” “Fed OASDI/EE,” “SS,” and “Social Security” all refer to the same 6.2% payroll tax.
What is the OASDI tax rate for 2026?
The OASDI tax rate is 6.2% for employees and 6.2% for employers (12.4% total). Self-employed workers pay the full 12.4% through SECA. The rate has been unchanged since 1990.
What is the OASDI wage base limit for 2026?
The 2026 OASDI wage base is $184,500, up from $176,100 in 2025. Earnings above this amount are not subject to OASDI tax, though Medicare tax still applies to all earnings with no cap.
Why did my OASDI withholding stop mid-year?
You hit the annual wage base limit. Once your year-to-date earnings reach $184,500 in 2026, your employer must stop withholding the 6.2% OASDI tax for the rest of the year. Withholding resumes on January 1. (Medicare withholding never stops.)
Do I get OASDI tax back if I work two jobs?
Possibly. The wage base applies per employer, so two jobs can cause over-withholding beyond the annual maximum ($11,439 per employee in 2026). You can claim the excess OASDI tax as a credit on your federal income tax return.
Conclusion
OASDI tax — the formal name for Social Security tax — is the 6.2% taken from your paycheck (matched by your employer) to fund retirement, survivor, and disability benefits. In 2026, it applies to the first $184,500 of your earnings, and it stops there — unlike Medicare tax, which has no cap.
Now that you know what that mysterious “OASDI” line on your pay stub means, you can read your paycheck with confidence: it’s not some obscure fee, but your contribution to the system that will one day pay benefits to you, your family, or someone unable to work. And if you’re self-employed, remember that the 12.4% SECA rate means planning ahead for this tax is one of the smartest financial moves you can make.