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Medicare Initial Enrollment Period: Dates and When Coverage Starts

The Initial Enrollment Period is your first and best chance to sign up for Medicare without penalty. It lasts 7 months.

Last reviewed October 30, 2026 · Figures from SSA.gov and CMS.gov

7 monthsLength of the IEP
3 + 1 + 3Months before, birth month, months after
10%Part B penalty per year if you delay without cover
65Age Medicare eligibility begins

How to find your dates

Your IEP starts 3 months before the month you turn 65, includes your birthday month, and ends 3 months after it.

If you turn 65 onIEP opensIEP closes
June 15, 2026March 1, 2026September 30, 2026
January 20, 2027October 1, 2026April 30, 2027
September 5, 2027June 1, 2027December 31, 2027

If your birthday is on the 1st of the month, Medicare counts you as turning 65 the day before, so your IEP shifts one month earlier. You can check your own dates with the enrollment calculator.

When your coverage starts

When you sign upCoverage begins
During the 3 months before your birthday monthThe first day of your birthday month
In your birthday month or the 3 months afterThe first day of the month after you sign up

Signing up early avoids a gap. If you wait until your birthday month or later, there is a delay of up to a month.

Automatic enrollment

If you already receive Social Security (or Railroad Retirement) benefits at least 4 months before you turn 65, you are enrolled in Parts A and B automatically, and your card arrives about 3 months before your birthday. If you are not yet collecting benefits, you must sign up yourself.

If you are still working

If you or your spouse are working and have employer health coverage, you may be able to delay Part B without a penalty and use a Special Enrollment Period later. See the Special Enrollment Period guide. Part A is premium-free for most people, so many sign up for it at 65 anyway.

HSA warning: If you contribute to a Health Savings Account, stop contributions at least 6 months before you apply for Medicare. Part A can be backdated up to 6 months, and contributing during that time can trigger a tax penalty.
Missing the window can be permanent. If you do not qualify for a Special Enrollment Period, Part B costs 10% more for every full 12 months you could have enrolled, for as long as you have Part B.

Related guides

Official sources