You must sign up for Medicare during your enrollment period, or you will face late penalties for the rest of your life

Medicare enrollment is tied to your 65th birthday. If you are already receiving Social Security or Railroad Retirement Board benefits when you turn 65, you are signed up automatically — you do not need to do anything. If you are not yet receiving benefits, you have a window of time around your 65th birthday to sign up yourself. Miss that window, and you will owe a permanent penalty on your premiums.

The exact timing depends on whether you are still working and whether you have health coverage through your job. These circumstances can extend your enrollment period, but only if you act within the allowed timeframe. The penalty itself does not go away — it stays on your account for as long as you are enrolled in Medicare.

Key Takeaways

  • If you receive Social Security or Railroad Retirement Board benefits, Medicare is automatic at 65 and requires no action on your part.
  • If you do not receive those benefits, you must sign up during your Initial Enrollment Period, which runs three months before your 65th birthday through three months after.
  • If you have health coverage through your current job, you may delay Part B enrollment without penalty, but you must tell Medicare about your work coverage.
  • Missing your enrollment period triggers a permanent 10 percent penalty on Part B premiums for each year you were may be able to access but not enrolled.
  • You can sign up online at Medicare.gov, by phone at 1-800-MEDICARE, or in person at your local Social Security office.

Your Initial Enrollment Period: The Three-Month Window

Your Initial Enrollment Period is seven months long: it starts three months before the month you turn 65 and ends three months after. For example, if you turn 65 in June, your period runs from March through September. During this window, you can sign up for Medicare Part A (hospital insurance) and Part B (medical insurance) without any penalty, even if you do not need coverage right away.

You must act during this window if you are not automatically enrolled. Signing up after your Initial Enrollment Period closes triggers a permanent penalty on Part B premiums. 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. That penalty stays with you for life, even if you switch plans later.

Part A (hospital insurance) also carries a penalty if you sign up late, but the penalty applies only if you did not have coverage through a spouse's job. If you worked and had employer coverage, you may have a grace period — but you still need to notify Medicare that you had that coverage.

When You Can Delay Without Penalty: The Work Exception

If you are still working and covered by your employer's health plan, you can delay Part B enrollment without penalty. This is called creditable coverage. The rule applies only if your employer has 20 or more employees. If your employer is smaller, you must enroll in Medicare Part B when you turn 65, even if you have coverage through the job.

To use this exception, you must tell Medicare that you have work coverage. You do this by contacting Social Security or Medicare directly — straightforward having the coverage is not enough. When you eventually leave your job or lose the coverage, you have eight months to sign up for Part B without penalty. If you wait longer than eight months, the permanent penalty kicks in.

Your spouse's work coverage does not count toward this exception. If your spouse is still working and you are not, you must enroll in Medicare at 65 unless you have your own employer coverage.

Automatic Enrollment: When You Do Not Need to Act

If you are already receiving Social Security benefits when you turn 65, Medicare Part A and Part B are automatic. You will receive your Medicare card in the mail about three months before your 65th birthday. You do not need to sign up, call anyone, or fill out forms. The same is true if you receive Railroad Retirement Board benefits.

Even though enrollment is automatic, you should still review your Medicare card when it arrives to make sure the information is correct. If you notice an error — a misspelled name, wrong date of birth, or missing information — contact Social Security to have it corrected before your coverage begins.

If you are not yet receiving Social Security or Railroad Retirement Board benefits, you will not be automatically enrolled. You must sign up yourself during your Initial Enrollment Period.

How to Sign Up: Three Ways to Enroll

You can sign up for Medicare online, by phone, or in person. The fastest method is usually online at Medicare.gov. Go to the "Sign Up for Medicare" section, create an account, and follow the prompts. You will need your Social Security number, date of birth, and citizenship or immigration status. The online process takes about 15 minutes.

You can also call 1-800-MEDICARE (1-800-633-4227) to sign up by phone. A representative will walk you through the enrollment questions and confirm your information. The call typically takes 20 to 30 minutes. This option is useful if you have questions about your specific situation or need help understanding your choices.

A third option is to visit your local Social Security office in person. You will need to bring your Social Security card, proof of citizenship or immigration status, and proof of age. Walk-in appointments are usually available, but you can also call ahead to schedule a time. This method works well if you prefer to handle things face-to-face or if you have complex circumstances.

What Happens If You Miss Your Enrollment Period

If you do not sign up during your Initial Enrollment Period and you do not have a valid reason for the delay, you will owe a permanent penalty. For Part B, the penalty is 10 percent of the standard monthly premium for each full year you were may be able to access but not enrolled. If the standard Part B premium is $165 per month and you were may be able to access for three years without enrolling, your penalty would be 30 percent — an extra $49.50 per month for life.

You can still sign up after your Initial Enrollment Period ends, but only during the General Enrollment Period, which runs January 1 through March 31 each year. Coverage would not begin until July of that year. The penalty applies unless you had creditable coverage through an employer or a spouse's employer during the time you were not enrolled.

The only other way to avoid the penalty is to show that you had a valid reason for missing your important date — for example, you were out of the country for an extended period, or you received incorrect information from a government agency. These exceptions are rare and require documentation. Contact Medicare to discuss your specific situation.

Special Enrollment Periods: When You Get Extra Time

Certain life events give you extra time to sign up for Medicare outside your Initial Enrollment Period. These are called Special Enrollment Periods. If you lose your employer coverage because you retire or are laid off, you have eight months to sign up for Part B without penalty. If you move out of your plan's service area, you have two months to switch plans. If you become a U.S. citizen, you have eight months to enroll.

Other may have access to events include losing coverage through a spouse's death, divorce, or loss of their employment. You must report the event to Medicare within the required timeframe — usually within 60 days — to preserve your right to enroll without penalty. Contact Medicare directly to report your event and confirm your new enrollment period.

If you are unsure whether your situation qualifies for a Special Enrollment Period, call 1-800-MEDICARE and describe what happened. The representative can tell you whether you are may be able to access for extra time and how long you have to act.

Frequently Asked Questions

Do I have to sign up for Medicare at 65 if I am still working?

If you have health coverage through your current job and your employer has 20 or more employees, you can delay Part B without penalty. You must notify Medicare that you have work coverage. When you leave your job, you have eight months to sign up for Part B. If you work for a small employer (fewer than 20 employees), you must enroll in Part B at 65 even if you have coverage through the job.

What if I turn 65 but am not yet receiving Social Security?

You must sign up for Medicare yourself during your Initial Enrollment Period. You do not need to be receiving Social Security benefits to enroll in Medicare. Contact Medicare.gov, call 1-800-MEDICARE, or visit your local Social Security office. You can sign up even if you have not yet filed for Social Security benefits.

Can I sign up for Medicare after I turn 65?

Yes, but only during the General Enrollment Period (January 1 through March 31 each year) if you missed your Initial Enrollment Period. Coverage would not start until July. You will owe a permanent penalty on Part B premiums unless you had creditable coverage through an employer during the time you were not enrolled.

What is the penalty for signing up late?

The Part B penalty is 10 percent of the standard monthly premium for each full year you were may be able to access but not enrolled. This penalty is permanent and stays on your account for as long as you are enrolled in Medicare. Part A also has a penalty in some situations, calculated differently based on how long you were not covered.

How do I know if my employer coverage counts as creditable coverage?

Creditable coverage through an employer applies only if your employer has 20 or more employees. Your employer's human resources or benefits department can confirm the company size. You must tell Medicare about your work coverage — straightforward having it does not protect you from penalties. Contact Medicare to report your coverage before you lose it.