When You Can Enroll in Medicare: Age Requirements and Timing

Medicare starts at age 65 for most people

Medicare is a federal health insurance program that becomes available to you at age 65, regardless of your work history or income. You do not have to wait until you retire — the program is there whether you keep working or stop. The month you turn 65, you enter a window to sign up, and your coverage can begin as early as the first day of that month.

If you were born on the first day of any month, Medicare considers your birthday to be the day before. This means your enrollment window actually opens three months before the month you turn 65. For example, if you were born on January 1, your window opens in October of the year you turn 64.

You can sign up through Medicare.gov, by phone at 1-800-MEDICARE, or in person at your local Social Security office. The process itself takes about 10 minutes online.

Key Takeaways

You become may be able to access for Medicare the month you turn 65, and you have a seven-month window to sign up without penalty.
If you delay signing up past your initial window, you may pay higher premiums for the rest of your life, even if you sign up later.
You can sign up online at Medicare.gov, by calling 1-800-MEDICARE, or at your local Social Security office.
Some people under 65 can get Medicare if they receive Social Security Disability Insurance (SSDI) for at least 24 months, or if they have end-stage renal disease or ALS.

What happens if you miss your initial sign-up window

Your initial enrollment window is seven months long: it starts three months before the month you turn 65 and ends three months after. If you do not sign up during this window, you will face a late enrollment penalty on your Part B premium (the part that covers doctor visits and outpatient care). The penalty is 10 percent of the standard Part B premium for each full year you were may be able to access but not signed up.

This penalty stays with you permanently. If you were supposed to sign up at 65 and did not sign up until age 72, you would pay the penalty for the rest of your life, even if you switch plans later. The only exception is if you had creditable coverage through an employer or union while you were working — in that case, you may not owe a penalty.

You can sign up anytime after your initial window closes, but the penalty applies when ready. There is no grace period to catch up without cost.

People under 65 who can get Medicare

You do not have to wait until 65 if you receive Social Security Disability Insurance (SSDI) for at least 24 months. Once you have been on SSDI for two years, you become may be able to access for Medicare automatically — you do not have to do anything. Your coverage begins in the 25th month of your SSDI benefits.

Two other groups can get Medicare before 65: people with end-stage renal disease (permanent kidney failure requiring dialysis or a transplant) and people with ALS (amyotrophic lateral sclerosis, also called Lou Gehrig's disease). People with ALS become may be able to access when ready upon diagnosis. People with end-stage renal disease have a three-month waiting period from the start of dialysis or from the month of a kidney transplant.

If you fall into one of these categories, you will need to sign up through Medicare.gov or by calling 1-800-MEDICARE. Social Security does not enroll you automatically for these conditions.

How to sign up before your 65th birthday

You can sign up as early as three months before the month you turn 65. The best time to do it is during the first month of your enrollment window — this gives you the most time to fix any problems before coverage starts. You will need your Social Security number, proof of citizenship or legal residency, and information about any current health coverage you have.

Online signup at Medicare.gov takes about 10 minutes. You can also call 1-800-MEDICARE and speak to a representative, or visit your local Social Security office in person. If you sign up in the month you turn 65, your coverage can start on the first day of that month. If you sign up after that month, your coverage will start the first day of the month after you sign up.

What to know about Part A and Part B enrollment

Part A (hospital insurance) and Part B (medical insurance) have different rules about penalties. Most people do not pay a premium for Part A if they or their spouse paid Medicare taxes while working. Part B has a monthly premium that changes each year, and the late enrollment penalty applies only to Part B.

When you sign up, you choose whether to enroll in Part B at the same time. If you are still working and have health coverage through your employer, you may be able to delay Part B without penalty — but you must have what Medicare calls creditable coverage, and you must sign up within eight months of leaving that job or losing the coverage. If you miss this important date, the Part B penalty applies.

Part A enrollment has no penalty for late signup, but you should still enroll as soon as you turn 65 to make sure you have coverage from day one.

Medicare coverage options once you turn 65

Once you are enrolled in Medicare, you choose between two paths: Original Medicare (Part A and Part B, run by the federal government) or a Medicare Advantage plan (Part C, run by private insurance companies). Most people stick with Original Medicare and add a separate prescription drug plan (Part D) and a supplemental plan (Medigap) to cover costs that Medicare does not pay.

You have until December 7 of the year you turn 65 to choose your plan. If you do not pick one, Medicare will enroll you in Original Medicare automatically. You can change your plan once a year during the annual enrollment period, which runs from October 15 to December 7.

Frequently Asked Questions

Can I sign up for Medicare before I turn 65?

Yes. Your enrollment window opens three months before the month you turn 65. You can sign up online at Medicare.gov, by phone at 1-800-MEDICARE, or at your local Social Security office. Signing up early gives you time to resolve any issues before your coverage starts.

What if I am still working at 65?

You can stay on your employer's health plan and delay Medicare Part B without penalty, but only if your employer has 20 or more employees. You must sign up for Part B within eight months of leaving that job or losing the coverage. If you miss this important date, you will pay a late enrollment penalty for the rest of your life.

Do I have to sign up for Part A and Part B at the same time?

No. You can enroll in Part A without Part B if you are still working and have employer coverage. However, most people enroll in both at 65. If you delay Part B, make sure you understand the eight-month window for signing up without penalty after you leave your job.

What is the late enrollment penalty for 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 not signed up. This penalty is permanent and stays with you even if you switch plans later. For example, if you were may be able to access at 65 and signed up at 70, you would pay a 50 percent penalty on top of your regular premium for life.

Can I get Medicare if I am under 65?

Yes, if you have received SSDI for at least 24 months, or if you have end-stage renal disease or ALS. People on SSDI become may be able to access automatically in the 25th month of benefits. People with end-stage renal disease or ALS must sign up through Medicare.gov or by calling 1-800-MEDICARE.

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.