Sign up for Medicare during your Initial Enrollment Period, which starts three months before the month you turn 65 and ends three months after

Your Initial Enrollment Period is a seven-month window centered on your 65th birthday month. If you turn 65 in June, your period runs from March through September. During this window, you can enroll in Medicare Part A (hospital insurance) and Part B (medical insurance) without penalty.

If you miss this window, you will pay a permanent penalty on your Part B premium for as long as you have Medicare — typically 10 percent more per year of delay. Part A has a similar penalty structure. The only exception is if you were covered by an employer health plan while working, in which case you have an eight-month grace period after that coverage ends to enroll without penalty.

You do not have to wait until you turn 65 to start the process. You can contact Social Security or Medicare three months before your birthday to begin enrollment. Many people complete it by mail or online in under an hour.

Key Takeaways

  • Your Initial Enrollment Period runs for seven months: three months before your 65th birthday month, the birthday month itself, and three months after.
  • Missing this window triggers a permanent 10 percent penalty on your Part B premium for each year you delay, with no way to remove it later.
  • If you have employer coverage when you turn 65, you have an eight-month grace period after that coverage ends to enroll without penalty.
  • You can start the enrollment process three months before your birthday by contacting Social Security or Medicare directly.

What happens if you miss your Initial Enrollment Period

If you do not enroll during your seven-month window and you do not have employer coverage, you will owe a late enrollment penalty on Part B. This penalty is 10 percent of the standard Part B premium for each full year you were may be able to access but not enrolled. If you were may be able to access for three years and did not sign up, your premium goes up 30 percent — and that increase stays with you permanently, even after you finally enroll.

Part A has a similar structure: a 10 percent penalty for each year of delay if you do not have employer coverage. The penalty applies to your monthly premium for as long as you have Part A.

There is one situation where you can avoid the penalty: if you were enrolled in a group health plan through your job or your spouse's job when you turned 65, you have eight months after that coverage ends to enroll in Medicare without penalty. This is called the Special Enrollment Period. You will need to show proof that you had employer coverage — usually a letter from your employer or health plan stating the coverage dates and that it was group health insurance.

Signing up before you turn 65

You can contact Medicare or Social Security three months before your 65th birthday to begin enrollment. This gives you time to review your options, ask questions, and complete the paperwork before your coverage needs to start.

Most people enroll online through Medicare.gov or by phone with Social Security at 1-800-772-1213. You will need your Social Security number, proof of citizenship or legal residency, and information about any current health coverage. The process typically takes 15 to 45 minutes, depending on whether you have questions about Part D (prescription drug coverage) or Medicare Advantage plans.

If you enroll during your Initial Enrollment Period, your coverage can start as early as the first day of the month in which you turn 65, or the first day of the following month if you enroll late in your birthday month. Timing your enrollment early means you will not have a gap in coverage.

When you have employer coverage at 65

If you are still working and covered by your employer's health plan when you turn 65, you do not have to enroll in Medicare right away. You can stay on your employer plan and delay Medicare enrollment until your employment or coverage ends, as long as your employer has 20 or more employees.

When your employer coverage ends — whether because you retire, leave the job, or the plan closes — you have eight months to enroll in Medicare without penalty. This eight-month window is your Special Enrollment Period. After those eight months, the standard late enrollment penalties explore.

Tell your employer's benefits department that you are turning 65 and ask whether you should enroll in Medicare while still employed. Some employers coordinate with Medicare automatically; others require you to handle it yourself. Getting this in writing protects you if there is a dispute later about when your coverage ended.

Spouse coverage and family situations

If your spouse is younger than 65 and covered under your employer plan, you can usually stay on that plan even after you turn 65. Your spouse's coverage does not change when you reach Medicare age. However, you should still enroll in Medicare Part A and Part B during your Initial Enrollment Period to avoid penalties, even if you do not use it when ready.

If you are divorced and your ex-spouse is 62 or older, you may be able to enroll in Medicare based on their work record. You do not need your ex's permission, and they do not need to be enrolled themselves. Your Initial Enrollment Period still applies, so the same seven-month window and penalty rules hold.

Part D and Medicare Advantage enrollment timing

Part D (prescription drug coverage) and Medicare Advantage (Part C, an alternative to Original Medicare) have their own enrollment rules that overlap with your Initial Enrollment Period. If you enroll in Original Medicare (Part A and Part B) during your seven-month window, you also have until the end of that same window to choose Part D or Medicare Advantage.

If you miss Part D enrollment and you do not have other creditable prescription drug coverage, you will pay a permanent penalty on your Part D premium — typically 1 percent of the national average premium per month of delay. This penalty is separate from your Part B penalty and also stays with you for life.

Medicare Advantage plans have their own annual enrollment period (October 15 to December 7 each year), but during your Initial Enrollment Period you can switch between Original Medicare and Medicare Advantage without waiting for the annual window.

How to confirm your enrollment status

After you enroll, you should receive a Medicare card in the mail within two to four weeks. Your card shows your Medicare number and which parts of Medicare you are enrolled in (A, B, D, or Advantage).

You can check your enrollment status anytime by logging into your Medicare account at Medicare.gov or by calling 1-800-MEDICARE (1-800-633-4227). Have your Social Security number ready. If there is an error — for example, if you enrolled in Part B but your card does not show it — contact Medicare when ready to correct it, because the penalty clock starts from your 65th birthday month regardless of when the card arrives.

Frequently Asked Questions

What if I turn 65 in the middle of a month?

Your Initial Enrollment Period still runs for seven months total. If you turn 65 on June 15, your period starts March 1 and ends September 30. You can enroll anytime during those seven months. Coverage can start as early as June 1 if you enroll by the end of May, or July 1 if you enroll in June or later.

Can I enroll in Medicare before I turn 65?

You can contact Medicare and Social Security three months before your birthday to start the process, but your coverage cannot start before the month you turn 65. Enrolling early just means you complete the paperwork ahead of time so there is no gap when your coverage should begin.

Do I have to enroll in Part B if I have employer coverage?

You can delay Part B enrollment if you have employer coverage through your job, but you should still enroll in Part A (hospital insurance) during your Initial Enrollment Period. Part A has no premium if you or your spouse paid Medicare taxes for 10 years, so there is no cost to enrolling and no reason to delay.

What if I miss my Initial Enrollment Period but have no employer coverage?

You can still enroll in Medicare after your seven-month window closes, but you will owe a permanent penalty on Part B (and Part A if applicable). The penalty is 10 percent per year of delay. You can enroll during the General Enrollment Period (January 1 to March 31 each year), with coverage starting July 1 of that year.

How do I know if my employer coverage counts as creditable coverage?

Creditable coverage means your employer plan is at least as good as Medicare. Your employer or health plan should tell you in writing whether your coverage is creditable. If you are unsure, ask your benefits department or contact Medicare at 1-800-MEDICARE before your Initial Enrollment Period ends.