You must enroll in Medicare at 65, but the penalty for missing the important date depends on how long you wait

Medicare enrollment is not optional once you turn 65, even if you are still working or covered by an employer plan. However, there are exceptions that let you delay without penalty. If you miss your enrollment window and do not may have access to for an exception, you will pay a higher premium for as long as you have Medicare — the penalty does not go away after a few years.

The key is understanding your own situation: whether you are covered by an active employer plan, whether you are already receiving Social Security, and whether you have had a may have access to life event. These facts determine whether you must enroll right at 65 or whether you can safely wait.

Key Takeaways

  • You must enroll in Medicare Part A and Part B during your Initial Enrollment Period, which runs three months before, the month of, and three months after your 65th birthday.
  • If you are covered by an active employer health plan through your own job, you can delay Part B enrollment without penalty as long as you enroll within eight months of losing that coverage.
  • Missing your enrollment window without a may have access to reason results in a permanent 10 percent increase to your Part B premium for each year you were may be able to access but not enrolled.
  • If you are already receiving Social Security before 65, you will be enrolled in Medicare automatically; you do not have to do anything.
  • Delaying Part A when you have no employer coverage will also trigger a penalty, so your only penalty-free delay option is Part B if you have active workplace insurance.

When you must enroll and what happens if you miss the important date

Your Initial Enrollment Period is seven months long: it starts three months before the month you turn 65 and ends three months after. During this window, you can enroll in Medicare Part A (hospital insurance) and Part B (medical insurance) without penalty, regardless of your health or any other factor.

If you do not enroll during those seven months and you do not have a may have access to exception, you will owe a penalty on Part B for the rest of your life. The 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 before enrolling, your premium goes up 30 percent permanently. This penalty stacks on top of the regular premium increase that happens every year.

Part A (hospital insurance) also carries a penalty if you delay without a may have access to reason: 10 percent per year for those without employer coverage. However, most people over 65 do not owe Part A premiums because they or their spouse paid Medicare taxes for at least 10 years while working, so the penalty is less commonly an issue.

The employer coverage exception: how to delay Part B without penalty

If you are still working at 65 and covered by your employer's health plan, you can delay Part B enrollment without penalty. This is the most common reason people legitimately wait past 65. The rule applies only if the coverage is based on your own current employment — coverage through a spouse's employer plan does not count.

Once you leave that job or lose the employer coverage, you have eight months to enroll in Part B. This eight-month window is separate from your Initial Enrollment Period. If you enroll within those eight months, no penalty applies. If you wait longer than eight months after losing coverage, the 10 percent annual penalty kicks in.

You must tell Medicare when you lose your employer coverage so the agency knows to start your eight-month grace period. You can report this through your Medicare.gov account, by phone at 1-800-MEDICARE, or in person at a Social Security office. Have your employer plan documents ready when you contact them.

Automatic enrollment if you are already receiving Social Security

If you are receiving Social Security benefits before you turn 65, Medicare will enroll you automatically in Part A and Part B about three months before your 65th birthday. You do not have to do anything, and you do not have to pay to enroll. Your Medicare card will arrive in the mail.

If you do not want Part B (for example, because you have employer coverage), you must actively decline it. Contact Social Security or Medicare in writing before your coverage starts to opt out. If you decline and later want to enroll, you will face the standard penalty unless you have a may have access to exception.

Life events that extend your enrollment window

Certain may have access to events give you two months to enroll in Medicare without penalty, even if you miss your Initial Enrollment Period. These include losing employer coverage, losing coverage through a family member's employment, moving out of your health plan's service area, or having your plan end.

You must enroll within two months of the event. Medicare will ask you to prove the event happened — usually a letter from your employer, your plan, or a government agency stating the date coverage ended. Keep documentation of any life event that affects your health insurance.

What happens if you enroll late and owe a penalty

If you enroll after your Initial Enrollment Period and you do not have a may have access to exception, Medicare will calculate your penalty based on how many months you were may be able to access but not enrolled. The penalty applies to Part B premiums (and Part A if applicable) for as long as you have Medicare.

The penalty does not expire or decrease over time. If you enrolled three years late, you will pay 30 percent more than the standard premium every month for the rest of your life. This is why it matters to understand your own situation and act before your important date passes.

You cannot appeal or remove the penalty after it is applied, so if you are unsure whether you need to enroll, contact Medicare before your important date rather than after. The call is free and takes a few minutes.

Part A versus Part B: which one you absolutely must have

Part A covers hospital stays, skilled nursing facility care, hospice, and home health services. Part B covers doctor visits, outpatient care, medical equipment, and preventive services. Most people need both, but the enrollment rules differ slightly.

If you have no employer coverage at 65, you should enroll in both Part A and Part B during your Initial Enrollment Period to avoid penalties on either one. If you have employer coverage, you can delay Part B but should still enroll in Part A unless you are still working and your employer plan is primary (meaning it pays first). Ask your employer's benefits office whether you need Part A while you are still covered by their plan.

Frequently Asked Questions

Can I delay Medicare if I am still working at 65?

Yes, but only Part B. You can delay Part B enrollment if you are covered by your employer's health plan based on your own current job. You must enroll within eight months of losing that coverage. Part A should still be enrolled during your Initial Enrollment Period unless your employer plan is primary and your employer confirms you do not need it.

What if I miss my enrollment important date but have no employer coverage?

You will owe a penalty on Part B (and possibly Part A) for the rest of your Medicare coverage. The penalty is 10 percent of the standard premium for each year you were may be able to access but not enrolled. Contact Medicare at 1-800-MEDICARE to enroll as soon as possible to stop the penalty from growing.

Do I have to enroll if I am on Medicaid?

Yes. Medicaid does not replace Medicare. You must enroll in Medicare at 65 even if you are receiving Medicaid. In most states, Medicare becomes your primary insurance and Medicaid fills in gaps. Contact your state Medicaid office and Medicare to coordinate your coverage.

What if I do not want Medicare and prefer to stay on my employer plan?

You can delay Part B, but you should still enroll in Part A during your Initial Enrollment Period unless your employer confirms you do not need it. When you eventually leave your job, you have eight months to enroll in Part B without penalty. After that window closes, the penalty applies.

Will Medicare contact me automatically to enroll?

Medicare will contact you automatically only if you are already receiving Social Security. Otherwise, it is your responsibility to enroll during your Initial Enrollment Period. You can enroll online at Medicare.gov, by phone at 1-800-MEDICARE, or in person at a Social Security office.