What is OASDI tax?
OASDI is Social Security tax under its legal name. Employees pay 6.2% until wages from that employer reach $184,500 in 2026. The most withheld is $11,439.
The name on the stub is the name in the statute
OASDI means Old-Age, Survivors, and Disability Insurance. That is the program people call Social Security. Payroll systems print OASDI because that is the statutory name, and it is the line that makes a person search the abbreviation from the break room. If the stub says SS or Social Security instead, it is this same 6.2% tax. FICA is this tax plus Medicare.
The tax stops when wages at that employer reach $184,500. The Social Security Administration set that wage base for 2026. Six point two percent of the full base is $11,439. After that, later checks from that employer show zero on the OASDI line. Medicare does not stop, and it is not part of the $11,439.
The week the line shrinks
Someone paid $5,000 a week has $310 of Social Security on an ordinary week, because 6.2% of $5,000 is $310. Near the wage base, one paycheck withholds only the slice still under $184,500, and the checks after that withhold none. Watch the year-to-date column. When OASDI year to date reaches $11,439, that employer is done for the year.
A raise late in the year can feel larger for this reason. Federal income tax and Medicare still come out. The 6.2% line may already be gone. The first paycheck of January brings it back, because the wage base starts over.
Two jobs, and one tax return
Each employer withholds as if it were the only job. Two employers can each take 6.2% until each, on its own, reaches $184,500. Combined wages can pass the base. The extra Social Security is claimed back on the federal tax return. The employers do not refund each other during the year. When both stubs are individually right, there is nothing on either stub to “fix.”
A traditional 401(k) does not reduce OASDI. Health insurance taken pre-tax through a cafeteria plan usually does, because those dollars were never Social Security wages. If the Social Security line looks short, those pre-tax dollars are the first place to look. How to check a pay stub walks that comparison with a $2,500 Texas check.
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Questions
Is OASDI the same as Social Security?
Yes. Stubs often say OASDI, SS, or Social Security for the same 6.2% line.
Does it stop mid-year?
Once taxable wages hit $184,500 at one employer, that employer stops withholding OASDI. Medicare does not stop.
Do two jobs share the cap?
Each employer withholds as if it were the only one. Extra Social Security can be reconciled on the tax return.
Does a 401(k) reduce OASDI?
A traditional 401(k) does not. A cafeteria-plan health deduction usually does.