The OASDI line on your pay stub is the federal payroll tax that funds Social Security. In 2026, you pay 6.2% of your wages up to $184,500, and your employer pays another 6.2% on the same wages, for a combined rate of 12.4%.1Social Security Administration. Contribution and Benefit Base OASDI stands for Old-Age, Survivors, and Disability Insurance. Every dollar withheld builds an earnings record that decides whether you qualify for Social Security later and how much you receive.
What the OASDI Tax Pays For
Three separate insurance programs run on your contributions, each tied to an event that can cut off income.
Retirement is the largest. Once you earn 40 credits over your working life, you qualify for monthly payments in retirement.2Social Security Administration. Social Security Credits and Benefit Eligibility The amount depends on your highest-earning years. For someone retiring at full retirement age in 2026, the maximum monthly benefit is $4,152.3Social Security Administration. What Is the Maximum Social Security Retirement Benefit Payable?
Survivors benefits go to the families of workers who die. Eligible spouses, children, and dependent parents can receive monthly checks.
Disability benefits go to workers who develop a medical condition that prevents them from working for at least 12 consecutive months. The Social Security Administration applies a strict test: you must be unable to do your previous work or adjust to other work because of your condition.4Social Security Administration. Disability Benefits – How Does Someone Become Eligible? Even after approval, there is a five-month waiting period before payments begin, with limited exceptions such as an ALS diagnosis or a prior disability period that ended within the last five years.5Social Security Administration. DI 10105.075 – When The Five Month Waiting Period Is Not Required
These are “earned” benefits: your lifetime earnings determine both whether you qualify and how much you get. The system is pay-as-you-go, meaning today’s workers fund today’s beneficiaries rather than building individual accounts.
How Much OASDI Comes Out of Your Paycheck
The math is a flat percentage applied to your earnings up to a cap. Congress set the employee rate at 6.2% and the employer rate at 6.2% by statute.6GovInfo. 26 USC 3101 – Rate of Tax That rate has not changed since 1990.
The cap is the Social Security wage base, and it adjusts each year based on the national average wage index. For 2026, the wage base is $184,500. Every dollar you earn above that amount is free of OASDI tax. The most any single worker will pay in 2026 is $11,439, and their employer will pay the same.1Social Security Administration. Contribution and Benefit Base
This is what separates OASDI from the Medicare Hospital Insurance tax, which applies to all earnings with no ceiling. Someone earning $300,000 stops paying OASDI partway through the year but keeps paying the 1.45% Medicare tax on every check.1Social Security Administration. Contribution and Benefit Base
If you are a W-2 employee, the process is invisible. Your employer withholds 6.2% from each paycheck and remits it along with the matching share. At year end, the total appears in Box 4 of your W-2, labeled “Social security tax withheld.” For 2026, that box should not exceed $11,439.7Internal Revenue Service. 2026 General Instructions for Forms W-2 and W-3
If You’re Self-Employed
Self-employed workers, including independent contractors and sole proprietors, owe the full 12.4% themselves because there is no employer to cover the other half.1Social Security Administration. Contribution and Benefit Base You calculate it on Schedule SE as part of the broader self-employment tax, which also includes the Medicare portion.8Internal Revenue Service. Self-Employment Tax (Social Security and Medicare Taxes) The $184,500 wage base still applies.
To soften paying both halves, the tax code lets you deduct the employer-equivalent portion (half of the self-employment tax) when calculating your adjusted gross income. That reduces your income tax, though not the self-employment tax itself.8Internal Revenue Service. Self-Employment Tax (Social Security and Medicare Taxes)
Because nobody is withholding for you, the IRS expects quarterly estimated payments. For 2026, the deadlines are April 15, June 15, September 15, and January 15, 2027. Missing them can trigger an underpayment penalty. You can generally avoid the penalty if you owe less than $1,000 at filing, or if you paid at least 90% of this year’s tax or 100% of last year’s (110% if your adjusted gross income exceeded $150,000).9Internal Revenue Service. Underpayment of Estimated Tax by Individuals Penalty
What If You Have Two Jobs
Each employer withholds 6.2% independently, with no idea what the other is doing. If your combined wages from all jobs exceed $184,500, you will overpay OASDI for the year. That overpayment is not lost. You claim the excess as a credit on your Form 1040 when you file your annual return.10Internal Revenue Service. Topic No. 608, Excess Social Security and RRTA Tax Withheld
One wrinkle: if a single employer overwithholds because of a payroll error, you cannot claim that excess on your tax return. You have to ask the employer to correct it directly. If they refuse, you can file Form 843 with the IRS to request a refund.10Internal Revenue Service. Topic No. 608, Excess Social Security and RRTA Tax Withheld
Who Doesn’t Pay OASDI
Most workers in the United States pay it. A handful of narrow exemptions exist.
- Members of a recognized religious sect that has opposed public or private insurance since before 1951, where the sect makes reasonable provision for its dependent members, can apply for an exemption. Doing so means waiving all rights to Social Security and Medicare benefits.11Social Security Administration. SSA Handbook 1128
- Nonresident alien students in F-1, J-1, or M-1 status who have been in the U.S. for fewer than five calendar years are generally exempt on wages tied to their visa purpose, such as on-campus employment or authorized practical training. The exemption ends once they become resident aliens.12Internal Revenue Service. Foreign Student Liability for Social Security and Medicare Taxes
- Students enrolled at least half-time who work for the same college or university where they take classes are generally exempt from FICA on wages from that job. The exemption disappears if you qualify as a “professional employee,” which typically means eligibility for benefits like retirement plan participation, paid leave, or reduced tuition beyond what teaching and research assistants receive.13Internal Revenue Service. Student FICA Exception
- Household employees paid less than $3,000 in cash wages during 2026 owe no OASDI on those earnings, and neither does the person paying them.14Social Security Administration. Employment Coverage Thresholds
Some state and local government employees hired before certain dates may also be exempt if their employer never opted into Social Security coverage, though this affects a shrinking group.
Will Your Benefits Be Taxed Later
One thing surprises many people. After paying OASDI your entire working life, you may owe income tax on the benefits you eventually collect. The IRS uses a figure called “combined income” to decide. Combined income is your adjusted gross income, plus any tax-exempt interest, plus half of your Social Security benefits.
If your combined income exceeds $25,000 as a single filer or $32,000 as a married couple filing jointly, up to 85% of your benefits can become taxable income.15Social Security Administration. Must I Pay Taxes on Social Security Benefits? Those thresholds have never been adjusted for inflation since they were set in the 1980s and 1990s, so they catch more retirees every year. If your only income is a modest Social Security check, you likely owe nothing. If you have a pension, 401(k) withdrawals, or investment income alongside benefits, plan on at least some of those benefits being taxed.