Medicare Initial Enrollment Period (IEP)
The Initial Enrollment Period (IEP) is your first chance to sign up for Medicare — a 7-month window built around your 65th birthday. Getting the timing right protects you from gaps in coverage and lifelong penalties.
The 7-month window
Your IEP spans seven months: the three months before the month you turn 65, your birthday month, and the three months after. For most people this is the simplest time to enroll, because you have guaranteed access to Part A, Part B, Medicare Advantage, Part D, and your one-time Medigap open enrollment window.
When your coverage begins
Sign up before your birthday month and coverage starts the first day of your birthday month. Sign up during or after your birthday month and coverage starts the first of the month after you enroll. Enrolling early in your window is the safest way to have coverage in place on day one.
If you are still working at 65
If you have creditable employer coverage, you may be able to delay Part B without penalty and enroll later through a Special Enrollment Period. Most people still take premium-free Part A at 65. Confirm your coverage qualifies before delaying — guessing wrong triggers penalties.
Penalties for waiting
Miss your IEP without creditable coverage and you may have to wait for the General Enrollment Period, plus pay a permanent Part B penalty (10% per missed 12-month period) and a separate Part D penalty. See the full first-year checklist to stay on track.
Frequently Asked Questions
How long is the Initial Enrollment Period?
Seven months. It begins three months before the month you turn 65, includes your birthday month, and ends three months after.
When does my coverage start if I sign up during my IEP?
If you enroll in the three months before your birthday month, coverage starts the first day of your birthday month. If you enroll during or after your birthday month, coverage starts the first of the month after you sign up.
Do I have to enroll at 65 if I am still working?
Not necessarily. If you have creditable coverage from a current employer (yours or your spouse’s), you may delay Part B without penalty and use a Special Enrollment Period later. Confirm your coverage is creditable before delaying.
What is the penalty for missing my IEP?
Without creditable coverage, the Part B late-enrollment penalty adds 10% to your premium for each full 12-month period you could have had Part B but did not — and it lasts as long as you have Part B. Part D has a separate, permanent penalty.
Talk to a Licensed Medicare Advisor
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Get My Free ReviewThis information is for educational purposes only and is not legal, tax, or insurance advice. Medicare rules, premiums, and income thresholds change annually — confirm current figures with Medicare.gov, the Social Security Administration, or a licensed advisor. HealthPlan Connect is not affiliated with or endorsed by the federal Medicare program or any government agency. Last reviewed 2026-06-15 by Lynsey Brennan, Licensed Medicare Advisor (FL #G007269).