OASDI Tax: What It Is, How It Works, and Who Pays It
Last updated 06/02/2026 by
Ante Mazalin
Edited by
Andrew Latham
Summary:
OASDI tax is the federal payroll tax that funds the Social Security program, formally called Old-Age, Survivors, and Disability Insurance, deducted from every paycheck at a rate of 6.2% on wages up to the annual earnings cap.
It operates as a matched tax with three distinct functions.
- Old-Age Insurance: Funds monthly retirement benefits for workers who have accumulated enough work credits, starting as early as age 62.
- Survivors Insurance: Provides benefits to a deceased worker’s spouse, children, and dependents when the worker had sufficient earnings history.
- Disability Insurance: Pays monthly benefits to workers who become unable to work due to a qualifying medical condition before reaching retirement age.
Most workers see OASDI on their pay stub without knowing what it means. It is the Social Security line item — the tax that builds the earnings record that determines your retirement and disability benefit amounts later in life.
OASDI tax rate and wage base
The OASDI tax is split equally between employees and employers. According to the Social Security Administration, each side pays 6.2%, for a combined rate of 12.4% on covered wages.
The tax applies only up to the annual contribution and benefit base, which adjusts each year for wage inflation.
| Year | OASDI Wage Base | Employee Rate | Employer Rate | Max Employee Tax |
|---|---|---|---|---|
| 2022 | $147,000 | 6.2% | 6.2% | $9,114 |
| 2023 | $160,200 | 6.2% | 6.2% | $9,932 |
| 2024 | $168,600 | 6.2% | 6.2% | $10,453 |
| 2025 | $176,100 | 6.2% | 6.2% | $10,918 |
Wages above the annual cap are not subject to OASDI tax. A worker earning $250,000 in 2025 pays OASDI tax on the first $176,100 only. The Medicare portion of the payroll tax has no wage cap and applies to all earnings.
OASDI tax vs. FICA tax: what is the difference
FICA (Federal Insurance Contributions Act) is the umbrella law that authorizes two separate payroll taxes. OASDI is one of them; Medicare (also called HI, or Hospital Insurance) is the other. Together, they make up the FICA line on your pay stub.
| Tax | Program It Funds | Employee Rate | Wage Cap (2025) |
|---|---|---|---|
| OASDI | Social Security (retirement, survivors, disability) | 6.2% | $176,100 |
| Medicare (HI) | Hospital Insurance (Medicare Parts A and B) | 1.45% | None |
| Additional Medicare Tax | Medicare (high earners only) | 0.9% | Applies above $200K single / $250K MFJ |
Your total FICA withholding on a typical paycheck combines the 6.2% OASDI rate and the 1.45% Medicare rate, for 7.65% total. Your employer matches this 7.65% separately, making the combined FICA contribution 15.3% of covered wages.
Pro Tip
If you work multiple jobs and your combined wages exceed the OASDI wage base, you may overpay OASDI tax during the year because each employer withholds independently without knowing about the others. When you file your federal return, excess OASDI withholding is treated as a tax payment and applied to your refund or tax due. You cannot claim a refund for the employer’s matching share — only your own employee-side overpayment.
OASDI tax for self-employed workers
Self-employed individuals pay both the employee and employer portions of OASDI tax through the Self-Employment Contributions Act (SECA) tax. The combined rate is 12.4% on net self-employment earnings, up to the same annual wage base that applies to employees.
The IRS allows self-employed workers to deduct half of their self-employment tax when calculating adjusted gross income, which partially offsets the additional burden relative to employees. This deduction appears on Schedule 1 of Form 1040 and reduces taxable income but not the self-employment tax itself.
Self-employed workers report and pay OASDI through Schedule C and Schedule SE, filed with their annual federal return. Those expecting to owe more than $1,000 in taxes should make quarterly estimated tax payments to avoid underpayment penalties.
How the OASDI tax builds your Social Security benefit
Every dollar of OASDI tax you pay is tied to an earnings record maintained by the Social Security Administration. That record determines your eventual benefit through a formula called the Primary Insurance Amount (PIA), which calculates your average indexed monthly earnings over your highest 35 earning years.
Paying more OASDI tax generally means a higher eventual benefit, up to the program’s maximum. Gaps in your earnings history — years with no or very low reported wages — reduce your average and lower your benefit. This is why continuing to work, even part-time, in higher-earning years can meaningfully increase your projected Social Security payout.
Who is exempt from the OASDI tax
Not all workers pay OASDI. Several categories of workers are exempt under federal law or treaty provisions.
- Certain government employees: Some state and local government workers hired before 1984 who participate in alternative public pension systems are exempt from OASDI. Federal civil service workers hired before 1984 who are covered by the Civil Service Retirement System are also exempt.
- Students working for their school: Students enrolled in and regularly attending classes at the school where they work may be exempt from FICA taxes on those wages.
- Nonresident aliens on specific visa types: Nonresident aliens on F-1, J-1, M-1, and Q-1 visas are generally exempt from OASDI tax on wages earned in the U.S.
- Religious order members: Members of certain recognized religious orders who take a vow of poverty may be exempt.
- Qualifying railroad workers: Railroad workers covered by the Railroad Retirement Act pay into a separate system and are not subject to OASDI.
Good to know: Some workers who are exempt from OASDI tax — such as certain government employees — may not be eligible for Social Security retirement benefits unless they have also accumulated enough work credits through other covered employment. Before assuming you will receive Social Security benefits in retirement, verify your earnings record and projected benefit at SSA.gov, where you can create a free account to view your annual Social Security statement.
Frequently asked questions
What does OASDI stand for?
OASDI stands for Old-Age, Survivors, and Disability Insurance. It is the formal program name for Social Security’s three insurance functions: retirement benefits for older workers, survivor benefits for families of deceased workers, and disability benefits for workers who can no longer work due to a qualifying medical condition.
Is OASDI the same as Social Security tax?
Yes. OASDI tax and Social Security tax refer to the same thing. “OASDI” is the formal policy name; “Social Security tax” is how most workers and employers refer to it in everyday usage. Both describe the 6.2% employee payroll deduction that funds Social Security benefits.
Why does OASDI stop being withheld mid-year for some workers?
Once your wages exceed the annual OASDI wage base — $176,100 in 2025 — your employer stops withholding OASDI for the remainder of the year. You have hit the cap. This is why high-income workers sometimes notice their take-home pay increases mid-year: the 6.2% OASDI withholding stops, while Medicare withholding continues on all wages with no ceiling.
Does OASDI tax count toward my Social Security retirement benefit?
Yes, directly. Every year of OASDI-covered wages is recorded in your Social Security earnings record. Your eventual retirement benefit is calculated using your highest 35 years of indexed earnings from that record. Paying more OASDI tax over your working life, and avoiding long gaps in covered employment, generally produces a higher monthly benefit at retirement.
Can you get a refund of OASDI tax overpaid?
If you overpaid OASDI tax as an employee — typically because you worked multiple jobs and your combined wages exceeded the wage base — you claim the excess on your federal income tax return (Form 1040, Schedule 3) as a credit against taxes owed or a refund. If a single employer over-withheld OASDI in error, request a correction from that employer first; they can adjust the W-2 and file corrected payroll forms.
Related reading on payroll taxes and income
- Social Security — explains how the benefits funded by OASDI tax work, including the retirement, survivors, and disability programs the tax supports.
- Federal income tax — the separate income tax withheld from wages, distinct from OASDI and Medicare payroll taxes.
- Gross income — your total earnings before OASDI, Medicare, and income tax withholdings are deducted.
- Adjusted gross income — the income figure used on your federal tax return, reduced by the self-employment tax deduction that partially offsets OASDI for the self-employed.
- Net income — your take-home pay after OASDI, Medicare, federal income tax, and other withholdings are removed.
Key takeaways
- OASDI tax is the 6.2% employee payroll deduction (matched by employers at 6.2%) that funds Social Security retirement, survivors, and disability benefits.
- The tax applies only up to an annual wage base that adjusts each year for inflation — $176,100 in 2025. Wages above the cap are not subject to OASDI.
- Self-employed workers pay both the employee and employer shares at a combined 12.4% rate through the SECA tax, with a deduction for half the amount on their federal return.
- OASDI is one of two taxes under FICA — the other is Medicare (1.45%), which has no wage cap.
- Workers with multiple jobs may overpay OASDI during the year and can claim excess withholding as a credit on their federal tax return.
For a broader look at how payroll taxes and other federal tax obligations affect Americans, see SuperMoney’s tax relief industry study.
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