When to Sign Up for Medicare: Timing That Protects You From Penalties

Sign up for Medicare in the three months before the month you turn 65

The window that matters most is your Initial Enrollment Period — the three months before you turn 65, the month you turn 65, and the three months after. If you sign up during this seven-month window, your coverage starts on the first day of the month you turn 65, with no penalty.

If you miss this window, you will pay a permanent penalty on your Part B and Part D premiums for as long as you have Medicare. The penalty is 10 percent of the Part B premium for each full year you were may be able to access but did not sign up, and 1 percent of the Part D premium for each month you went without coverage. These penalties do not go away if you sign up later.

The one exception: if you or your spouse are still working and covered by an employer health plan, you may be able to delay without penalty. But you must sign up within eight months of losing that coverage or retiring, whichever comes first. This is called a Special Enrollment Period, and it requires proof from your employer that you had group coverage.

Key Takeaways

Your Initial Enrollment Period runs for seven months: three months before you turn 65, the month of your birthday, and three months after.
If you miss your Initial Enrollment Period, you will pay a permanent penalty on Part B and Part D premiums for the rest of your life.
If you are still working and covered by your employer's health plan, you can delay Medicare without penalty, but only if you sign up within eight months of losing that coverage.
You can sign up online at Medicare.gov, by phone at 1-800-MEDICARE, or in person at your local Social Security office.
Part A (hospital insurance) is usually free if you or your spouse paid Medicare taxes for at least 10 years, but you must still sign up to receive it.

What happens if you work past 65

If you are still employed and your employer has 20 or more employees, your employer's health plan is the primary payer — it pays first, and Medicare pays second. You do not have to sign up for Medicare while you are working, and you will not face a penalty for delaying, as long as you sign up within eight months of leaving that job.

If your employer has fewer than 20 employees, Medicare becomes primary, and you should sign up for Part A and Part B when you turn 65. You can still delay Part D (prescription drug coverage) without penalty if your employer plan covers drugs at least as well as Medicare does — but you will need a letter from your employer stating this.

The risk of waiting: if you forget to sign up after you leave your job, the eight-month window closes and you face the permanent penalty. Mark your calendar for the month you plan to retire, and contact Social Security or Medicare at least two months before.

How to sign up and what documents you need

You have three ways to sign up: online at Medicare.gov, by phone at 1-800-MEDICARE (1-800-633-4227), or in person at your local Social Security office. Online is fastest — you can complete the form in 10 to 15 minutes if you have your information ready.

Have these documents or information on hand: your Social Security number, your birth date, your citizenship or immigration status, and information about any current health coverage (employer plan, Medicaid, or Veterans benefits). If you are signing up for Part A only, you may need proof that you or your spouse worked and paid Medicare taxes — Social Security has this on file, but you can bring a tax return or W-2 if you want to be certain.

If you sign up online, you will get a confirmation number when ready. If you sign up by phone or in person, ask for a receipt or confirmation. Keep this document — you will need it if there are questions later about your enrollment date.

Part A versus Part B: which one requires when ready action

Part A (hospital insurance) is usually free if you or your spouse paid Medicare taxes for at least 10 years. You must still sign up to receive it, but there is no monthly premium and no penalty for signing up late — you straightforward start coverage the month you sign up.

Part B (medical insurance for doctor visits and outpatient care) has a monthly premium that increases if you delay. The penalty applies even if you do not sign up for Part B until age 70. This is the coverage where the permanent penalty hits hardest, so signing up during your Initial Enrollment Period is the priority.

If you have low income, you may be able to get help paying your Part B premium through a program called Savings Programs. These are run by your state, and you can find your state program at Medicare.gov or by calling 1-800-MEDICARE.

Special cases: disability, end-stage renal disease, and ALS

If you are under 65 and receive Social Security Disability Insurance (SSDI) or are a railroad retirement beneficiary, you become may be able to access for Medicare automatically after 24 months of receiving benefits. You do not need to sign up — Medicare starts on the 25th month of your disability benefits.

If you have end-stage renal disease (ESRD) or ALS (amyotrophic lateral sclerosis), you may be able to sign up for Medicare before 65. Contact Social Security or Medicare to find out whether you may have access to and what the enrollment process is in your situation.

What to do if you missed your enrollment window

If you are past your Initial Enrollment Period and do not have a Special Enrollment Period (because you were not covered by an employer plan), you can still sign up during the General Enrollment Period, which runs from January 1 to March 31 each year. Coverage starts July 1 of that year. You will pay the permanent penalty on Part B and Part D unless you have a may have access to reason for the delay.

may have access to reasons are rare and specific — they include being incorrectly told by Social Security or Medicare that you did not need to sign up, or being unable to sign up due to a serious illness. If you believe you have a may have access to reason, contact Social Security or Medicare and ask them to review your case. Bring documentation of the reason (a letter from Social Security, medical records, or other proof).

If you cannot afford the penalty, there is no waiver or reduction process. The penalty is permanent. This is why signing up during your Initial Enrollment Period, even if you do not plan to use Medicare right away, is the safest choice.

Frequently Asked Questions

Do I have to sign up for Medicare if I am still working and have employer coverage?

No, if your employer has 20 or more employees. Your employer plan is primary, and you can delay Medicare without penalty. But sign up within eight months of leaving that job or retiring. If your employer has fewer than 20 employees, you should sign up for Part A and Part B at 65, though you can delay Part D if your employer covers drugs.

What is the penalty for signing up late, and is it permanent?

The penalty is 10 percent of the Part B premium for each full year you were may be able to access but did not sign up, and 1 percent of the Part D premium for each month you went without coverage. Yes, it is permanent — it stays on your premiums for life. There is no way to remove it.

Can I sign up for just Part A and skip Part B?

Yes. Part A is usually free and has no penalty for late signup. But if you later decide you want Part B, you will face the permanent penalty unless you sign up during a Special Enrollment Period (such as within eight months of losing employer coverage). Most people sign up for both during their Initial Enrollment Period to avoid this risk.

What if I turn 65 in the middle of the month — when does my coverage start?

If you sign up during your Initial Enrollment Period, coverage starts on the first day of the month you turn 65, regardless of the date within the month. If you sign up after your Initial Enrollment Period, coverage starts the first day of the month after you sign up.

Can I sign up for Medicare online, or do I have to go to an office?

You can sign up online at Medicare.gov, by phone at 1-800-MEDICARE, or in person at your local Social Security office. Online is the fastest option and takes about 10 to 15 minutes. You will get a confirmation number right away.

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.