What Age You Need to Be for Medicare

You become may be able to access for Medicare when you turn 65, with very few exceptions

Medicare may be able to access is tied to age 65 for most people. When you reach 65, you can enroll in Medicare Part A (hospital insurance) and Part B (medical insurance) regardless of your work history or health status. The enrollment window opens three months before your 65th birthday and closes three months after, so you have a seven-month window to sign up.

If you wait past this window to enroll, you may face a permanent penalty on your Part B premiums — an extra 10 percent for each year you delayed. Part A typically has no penalty if you have worked and paid Medicare taxes, but the rules differ if you have not worked enough quarters.

A small number of people become may be able to access before 65. If you have been receiving Social Security Disability Insurance (SSDI) for 24 months, you become may be able to access at any age. If you have end-stage renal disease (ESRD) or ALS (amyotrophic lateral sclerosis), you can enroll when ready regardless of age.

Key Takeaways

Most people become may be able to access for Medicare at age 65, and you should enroll during the seven-month window that starts three months before your birthday.
Delaying Part B enrollment past your initial window can result in a permanent 10 percent premium increase for each year you wait.
You can enroll in Medicare before 65 if you have been on SSDI for 24 months, have end-stage renal disease, or have ALS.
You do not need to retire or stop working to enroll in Medicare at 65, though your coverage and costs may differ if you are still employed.

How the enrollment window works

Your Initial Enrollment Period (IEP) lasts seven months: three months before the month you turn 65, the month you turn 65, and three months after. During this time, you can enroll in Part A and Part B without penalty, even if you are still working.

If you miss this window, you enter the General Enrollment Period (GEP), which runs January 1 through March 31 each year. You can enroll during GEP, but you will pay a late enrollment penalty on Part B. The penalty is 10 percent of the standard Part B premium for each full year you were may be able to access but did not enroll. This penalty is permanent — it stays on your bill for as long as you have Part B.

Example: If you turn 65 in June 2024 but do not enroll until March 2025, you have missed your IEP and will pay the penalty. If you enroll in January 2026 during the next GEP, you will have delayed two full years, so your penalty would be 20 percent of the standard premium.

When you are still working at 65

You can enroll in Medicare at 65 even if you are still employed and covered by your employer's health plan. However, the rules about when to enroll depend on the size of your employer and whether you want to delay enrollment.

If your employer has 20 or more employees, your employer coverage is considered primary, meaning it pays first. You can delay enrolling in Part B without penalty as long as you are actively employed and covered under your employer's plan. Once you leave that job, you have eight months to enroll in Part B without penalty — this is called the Special Enrollment Period (SEP).

If your employer has fewer than 20 employees, Medicare becomes primary at 65, and you should enroll even if you have employer coverage. Delaying enrollment in this case will trigger the late penalty.

Exceptions: Becoming may be able to access before 65

Three groups of people can enroll in Medicare before turning 65. The first group is people who have been receiving SSDI for at least 24 consecutive months. You do not need to be 65 — you become may be able to access automatically after the 24-month waiting period ends. Social Security will contact you about Medicare enrollment; you do not need to explore separately.

The second group is people with end-stage renal disease (ESRD) — permanent kidney failure requiring dialysis or a transplant. You become may be able to access for Medicare when ready upon diagnosis, regardless of age. You will need documentation from your doctor or dialysis center.

The third group is people with ALS, also called Lou Gehrig's disease. Unlike ESRD, you do not need to wait or meet any duration requirement — you become may be able to access as soon as you are diagnosed. Your doctor will need to confirm the diagnosis to Social Security.

What happens if you do not enroll at 65

If you do not enroll during your Initial Enrollment Period and you are not covered by an employer plan with 20 or more employees, you will face penalties. Part B premiums increase by 10 percent for each year you delayed. Part D (prescription drug coverage) also carries a late penalty — 1 percent of the national base beneficiary premium for each month you were without coverage, and this penalty is also permanent.

Beyond the financial penalty, you will have a gap in coverage. If you become ill or injured before you enroll, you will be responsible for the full cost of care. Medicare does not cover retroactively — it covers only from the date your coverage begins.

If you realize you missed your window, you can still enroll during the General Enrollment Period (January 1 through March 31), but your coverage will not start until July 1 of that year, and the penalties will explore.

Documents and information you will need

To enroll in Medicare, you will need your Social Security number, birth date, and citizenship or immigration status. You can enroll online through Medicare.gov, by phone at 1-800-MEDICARE, or in person at your local Social Security office.

If you are still working and want to delay Part B enrollment, you will need to provide proof of your employer coverage — usually a copy of your health insurance card or a letter from your employer's benefits department stating the number of employees and that you are actively employed.

If you are enrolling before 65 due to SSDI, ESRD, or ALS, Social Security will typically handle the enrollment process for you, but you should confirm your enrollment by checking your Medicare.gov account or calling 1-800-MEDICARE.

Questions to ask your doctor or Social Security

Before your 65th birthday, ask your doctor whether you have any conditions that might make you may be able to access for Medicare before 65. If you are on SSDI, ask Social Security when your 24-month waiting period ends and when Medicare enrollment will begin.

If you are still working, ask your employer's benefits department whether your company has 20 or more employees and whether your health plan will remain primary after you turn 65. This answer determines whether you can safely delay Part B enrollment.

If you have prescription drug coverage through your employer, ask whether it is considered creditable coverage under Medicare rules. If it is not, you may need to enroll in Part D at 65 to avoid a late penalty, even if you are delaying Part B.

Frequently Asked Questions

Can I enroll in Medicare before I turn 65?

Yes, but only in three situations: if you have been on SSDI for 24 months, if you have end-stage renal disease, or if you have ALS. Otherwise, you must wait until you turn 65. Social Security will contact you automatically if you may have access to early through SSDI.

What if I miss my enrollment window by a few weeks?

If you miss your seven-month Initial Enrollment Period, you can enroll during the General Enrollment Period (January 1 through March 31 each year), but your coverage will not start until July 1 and you will pay a permanent penalty on Part B. The penalty is 10 percent of the standard premium for each full year you delayed.

Do I have to retire to enroll in Medicare?

No. You can enroll in Medicare at 65 while still working. If your employer has 20 or more employees and you are actively employed, you can delay Part B enrollment without penalty. Once you leave that job, you have eight months to enroll without penalty.

What if my employer has fewer than 20 employees?

Medicare becomes primary at 65, so you should enroll in Part A and Part B even if you have employer coverage. Delaying enrollment will trigger a late penalty. Ask your employer's benefits department to confirm the company size if you are unsure.

Will I owe a penalty if I delay Part A?

Part A typically has no penalty if you have worked and paid Medicare taxes for at least 10 years (40 quarters). If you have not worked enough quarters, you may owe a premium for Part A, but this is different from a late enrollment penalty. Contact Social Security to find out how many quarters you have.

This guide is for general information only and is not medical, financial, legal, or other professional advice. For decisions specific to your situation, consult a qualified professional. See our Editorial Policy.