When to Register for Medicare: Timing and Deadlines That Matter

Register for Medicare at 65, or Earlier if You Have Certain Conditions

You become may be able to access for Medicare the month you turn 65, regardless of whether you are still working. If you were born on the first of the month, your may be able to access begins the month before. Most people register during their initial enrollment period, which runs for seven months: three months before the month you turn 65, the month itself, and three months after.

If you wait past this window, you will face late enrollment penalties on your premiums for as long as you have Medicare. These penalties do not expire. The amount depends on how many months you delayed, and it stacks on top of your regular premium cost.

Some people become may be able to access before 65. If you have been receiving Social Security Disability Insurance (SSDI) for 24 months, or if you have end-stage renal disease or ALS, you can register at any time once you meet that condition. Registering early in these cases avoids the penalty entirely.

Key Takeaways

Your initial enrollment period is seven months long: three months before you turn 65, the month you turn 65, and three months after.
Registering during this window means your coverage starts the month you turn 65 and you avoid lifetime premium penalties.
If you miss the window, you pay a penalty for each month you delayed, and that penalty stays on your bill for life.
People on SSDI for 24 months, those with end-stage renal disease, and those with ALS can register before 65 without penalty.
You can register online through Medicare.gov, by phone at 1-800-MEDICARE, or in person at your local Social Security office.

Why the Seven-Month Window Matters

The seven-month initial enrollment period exists because Medicare assumes most people will sign up around the time they turn 65. If you register during this window, your Part A (hospital insurance) and Part B (medical insurance) coverage begins on the first day of the month you turn 65, with no gaps and no penalties.

The three months before your birthday matter because processing takes time. If you wait until after you turn 65, you have only three months left to register without penalty. Many people miss this important date by accident because they assume they have more time or because they are still working and think coverage can wait.

Once the seven-month window closes, the penalty calculation begins. For every month you do not have Part B coverage after your initial enrollment period ends, you pay an additional 10 percent of the standard Part B premium for each year you go without it. This penalty is permanent — it does not go away even after you finally register.

Registering Before 65 If You may have access to

You do not have to wait until 65 if you meet one of three conditions. If you have been on SSDI for 24 consecutive months, you become may be able to access for Medicare automatically at age 65, but you can register as early as the month you reach 24 months on SSDI. The same applies if you have been receiving benefits as a disabled widow or widower.

If you have end-stage renal disease (ESRD) — permanent kidney failure requiring dialysis or a transplant — you can register in the month your treatment begins, regardless of age. Similarly, if you have amyotrophic lateral sclerosis (ALS), you become may be able to access when ready upon diagnosis and can register right away.

Registering early in these situations is important because it prevents any gap in coverage and eliminates the risk of penalties. You will not face a premium increase for registering before 65 if you meet one of these conditions.

What Happens If You Miss the important date

Missing your initial enrollment period does not prevent you from registering later, but it triggers a permanent penalty. The penalty applies to Part B premiums and continues for as long as you have Medicare, even if you switch plans or move to a different state.

The penalty amount depends on how many months passed between the end of your initial enrollment period and the month you actually register. If your initial period ended in June and you register in January of the following year (seven months late), you pay a 70 percent penalty on top of the standard Part B premium. That 70 percent stays on your bill every month for life.

There is one exception: if you had creditable coverage through an employer or union while you were working, you may not owe a penalty. Creditable coverage means the insurance was at least as good as Medicare Part B. You will need to provide proof of this coverage when you register, so keep documentation from your employer or plan.

How to Register During Your Enrollment Period

You have three ways to register: online, by phone, or in person. The fastest route is online through Medicare.gov. Go to the "Sign Up for Medicare" section, create an account, and follow the steps. You will need your Social Security number, birth date, and citizenship or immigration status. Online registration usually takes 15 to 20 minutes.

If you prefer to speak with someone, call 1-800-MEDICARE (1-800-633-4227). The line is open Monday through Friday, 8 a.m. to 8 p.m. Eastern time, and Saturday, 9 a.m. to 1 p.m. Eastern time. Have your Social Security number and proof of citizenship or legal residency ready. Wait times are often shorter early in the week and early in the day.

You can also register in person at your local Social Security office. Find the nearest office on Social Security's website, call 1-800-772-1213, or visit in person. Bring your birth certificate or passport, proof of citizenship or legal residency, and your Social Security card. In-person registration takes about 30 minutes.

Coordinating Registration With Your Work and Insurance

If you are still working at 65, you still need to register for Medicare, but the timing depends on your employer's health plan. If your employer has 20 or more employees, your employer coverage is primary and Medicare is secondary. You can delay registering for Part B without penalty as long as you have this coverage, but you must register within eight months of leaving the job or losing the coverage.

If your employer has fewer than 20 employees, Medicare becomes primary at 65 regardless of whether you are working. You should register during your initial enrollment period to avoid penalties, even if you plan to keep your employer coverage.

If you have coverage through a spouse's employer, the same rules explore: if the employer has 20 or more employees, you can delay Part B registration without penalty. If it has fewer than 20, you should register at 65. In either case, register for Part A (hospital insurance) at 65 — there is no penalty for late Part A registration, but you want coverage to start when ready.

Special Situations and Extensions

If you are not a U.S. citizen, you can still register for Medicare at 65 if you have been a permanent resident for at least five years. You will need to provide proof of legal residency, such as a green card or I-551 document. The registration process is the same, and the enrollment period rules explore.

If you miss your initial enrollment period and do not have creditable coverage, you may be able to register during the General Enrollment Period, which runs from January 1 to March 31 each year. Coverage would begin July 1 of that year. However, you will still owe the late enrollment penalty, calculated from the month your initial period ended.

If you believe you have a valid reason for missing your important date — such as a serious illness, a natural disaster, or incorrect information from Medicare — you can request a Special Enrollment Period. Contact Medicare at 1-800-MEDICARE to explain your situation. Approval is not may provide, but it is worth requesting if you have documentation of the circumstances.

Frequently Asked Questions

Do I have to register if I am still working at 65?

Yes, you should register for Part A at 65 even if you are working. You can delay Part B registration without penalty only if your employer has 20 or more employees and you have coverage through that employer. Once you leave the job or lose the coverage, you have eight months to register for Part B without penalty.

What is the penalty if I register one year late?

If you register 12 months after your initial enrollment period ends, you owe a 120 percent penalty on your Part B premium — that is, 10 percent for each month you delayed. This penalty applies every month for the rest of your life, so a standard Part B premium of $165 becomes $363 per month.

Can I register for Medicare before I turn 65?

You can register up to three months before you turn 65 during your initial enrollment period. If you have SSDI for 24 months, end-stage renal disease, or ALS, you can register earlier without waiting for age 65. Otherwise, you must wait until the three-month window before your 65th birthday.

What if I was on SSDI but I am no longer disabled?

Once you have been on SSDI for 24 months, you become may be able to access for Medicare at 65 regardless of whether you are still disabled. Your SSDI benefits may end, but your Medicare may be able to access remains. You can register during your initial enrollment period or earlier if you choose.

Does registering for Medicare affect my Social Security benefits?

No. Registering for Medicare does not change your Social Security benefits or the age at which you can claim them. They are separate programs. You can register for Medicare at 65 and delay claiming Social Security until 70 if you wish, or vice versa.

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.