What is OASDI on a pay stub?
OASDI on a pay stub is your Social Security tax. The letters stand for Old-Age, Survivors, and Disability Insurance, the formal name of the Social Security program. It is withheld from most wages together with Medicare tax; the two together are called FICA. Your employer pays a matching amount that does not come out of your pay.
What OASDI stands for
Old-Age, Survivors, and Disability Insurance. The Social Security Administration uses the name for the program that pays retirement, survivors and disability benefits. On a pay stub it may appear as OASDI, SS, SOC SEC or FICA-SS, depending on the payroll provider.
OASDI, Medicare and FICA
| Line on the stub | Program | Employer match |
|---|---|---|
| OASDI / SS | Social Security | Yes |
| MED / MEDI | Medicare | Yes (except Additional Medicare Tax) |
The IRS notes that only Social Security has a wage base limit: once your wages for the year pass it, OASDI stops being withheld until the next calendar year. Medicare has no wage base limit. The limit and the rates change, so this guide doesn’t quote them; the IRS topic listed below has the current figures.
Why the amount can change
- It is a percentage of your taxable wages, so it moves with your pay.
- Some pre-tax deductions reduce the wages it is charged on.
- It stops for the rest of the year once you reach the Social Security wage base.
Questions
Can I opt out of OASDI?
Not as a regular employee. Social Security tax is withheld from most wages by law. The exceptions are specific and set out in IRS guidance.
Sources
- Social Security Administration — Old-Age, Survivors, and Disability Insurance program reference
- IRS — Topic no. 751, Social Security and Medicare withholding rates
Official sources checked September 23, 2026. This guide explains how pay documents work; it is not tax or legal advice.