When to Enroll

Your Medicare Enrollment Timeline

Most people should enroll in Medicare around their 65th birthday, during what’s called the Initial Enrollment Period (IEP). This 7-month window begins three months before the month you turn 65, includes your birth month, and continues for three months after. Enrolling during this time helps you avoid potential delays in coverage and possible late enrollment penalties — especially for Medicare Part B (which covers doctor visits, outpatient care, and more) and Part D (prescription drug coverage).

Note: if your birthday is on the 1st of the month, your 7-month window surrounds the month prior to your birth month. For example, if you were born May 1st, you “age into” Medicare beginning April 1st.

If you’re already receiving Social Security or Railroad Retirement benefits when you turn 65, you’ll typically be enrolled in Parts A and B automatically. However, if you’re not yet collecting Social Security, you’ll need to actively sign up for Medicare through the Social Security Administration.

There are some exceptions to enrolling at age 65. If you’re still working and have employer coverage (or coverage through a spouse’s employer), you may be able to delay enrolling in Part B and/or Part D without penalty. But this depends on the size of the employer and whether the insurance is considered “creditable” coverage. Once you leave that coverage or retire, you’ll have a Special Enrollment Period (SEP) — usually lasting 8 months — to sign up for Medicare without penalties.

For those who miss both their Initial and Special Enrollment Periods, there’s a General Enrollment Period from January 1 to March 31 each year. Coverage begins the month after you enroll, and you may face late enrollment penalties that increase your costs permanently.