Medicare glossary
Initial Enrollment Period (IEP)
Your Initial Enrollment Period is the seven-month window when you first sign up for Medicare, centered on your 65th birthday: the three months before your birthday month, the month itself, and the three months after.
This is when most people enroll in Parts A and B and choose a Medicare Advantage or Part D plan. Signing up in the months before your birthday helps coverage begin without a gap. Missing this window without other qualifying coverage can lead to a permanent late-enrollment penalty.
Ready to compare?
Ready to compare real Medicare plans?
Enter your ZIP and we’ll take you to PlanMatch Medicare to compare the 2026 plans available where you live.