You are not automatically required to sign up for Medicare at 65, but waiting can cost you money in penalties for the rest of your life

Medicare enrollment is not automatic. You must take action during your 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 miss this window and do not have coverage through an employer or union, the government adds a permanent penalty to your monthly premium — 10 percent for every 12 months you were may be able to access but did not sign up. That penalty stays with you even after you finally enroll.

The one exception: if you are still working and covered by your employer's health plan, you can delay enrollment without penalty. But you must tell Medicare you have that coverage, or the penalty clock starts anyway.

Key Takeaways

  • You have seven months to sign up for Medicare starting three months before you turn 65; missing this window triggers a permanent 10 percent monthly premium penalty for each year you delay.
  • If you are covered by an active employer health plan, you can delay Medicare without penalty, but you must notify Medicare of that coverage during your Initial Enrollment Period.
  • Part A (hospital insurance) is usually free if you or your spouse paid Medicare taxes for 10 years, but Part B (doctor visits) costs money and requires a separate enrollment decision.
  • You can sign up online at Medicare.gov, by phone at 1-800-MEDICARE, or in person at your local Social Security office.
  • If you miss the important date, you can only sign up during the General Enrollment Period (January 1 to March 31 each year), and penalties will explore unless you had employer coverage.

When the seven-month window opens and closes

Your Initial Enrollment Period begins on the first day of the third month before you turn 65 and ends on the last day of the third month after. If you turn 65 in June, your window opens February 1 and closes September 30. You can enroll during any of those seven months; the month you turn 65 is not special.

The government counts this window strictly. If you miss September 30 in the example above, you cannot sign up again until January 1 of the following year, and even then only during the three-month General Enrollment Period. Any gap between your 65th birthday and when you finally enroll will trigger the penalty.

Part A versus Part B: which one you must choose

Part A covers hospital stays, skilled nursing, hospice, and home health care. Most people do not pay a monthly premium for Part A if they or their spouse worked and paid Medicare taxes for at least 10 years. Part A enrollment is usually automatic if you are already receiving Social Security, but you should confirm this during your Initial Enrollment Period.

Part B covers doctor visits, outpatient care, and medical equipment. Part B costs money — the standard premium in 2024 is $164.90 per month, though it varies by income — and you must actively choose to enroll. If you do not sign up during your Initial Enrollment Period and do not have employer coverage, you pay a 10 percent premium penalty for each 12-month period you were may be able to access but did not enroll. That penalty is permanent.

You can enroll in Part A without Part B, or Part B without Part A, though most people take both. If you have employer coverage, you can delay Part B without penalty, but delaying Part A when you are not working can still trigger a penalty.

Employer coverage: how to avoid the penalty

If you are still working at 65 and your employer offers health insurance, you can delay Medicare Part B without penalty. Your employer plan becomes your primary insurance, and Medicare becomes secondary. You must, however, tell Medicare during your Initial Enrollment Period that you have this coverage — do not straightforward skip enrollment and assume you are safe.

To notify Medicare of employer coverage, you can call 1-800-MEDICARE, visit Medicare.gov, or go to your local Social Security office. Bring your employer health plan documents so Medicare can confirm the coverage is active. If you do not notify Medicare and later try to claim you had employer coverage, you may still face a penalty unless you can prove the coverage existed.

Once you leave your job or your employer coverage ends, you have eight months to sign up for Medicare Part B without penalty. This is called a Special Enrollment Period. The clock starts the month after your employment or coverage ends.

How to sign up during your Initial Enrollment Period

You have three ways to enroll: online, by phone, or in person. Online enrollment through Medicare.gov is the fastest; you can complete it in 10 to 15 minutes and receive confirmation when ready. You will need your Social Security number, date of birth, and citizenship or immigration status.

By phone, call 1-800-MEDICARE (1-800-633-4227). Representatives are available 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 date of birth ready. Processing by phone takes the same time as online but you get verbal confirmation instead of a written one.

In person, visit your local Social Security office. You can find the nearest office at ssa.gov or by calling 1-800-772-1213. Bring your Social Security card, birth certificate, and proof of citizenship (passport, naturalization papers, or state ID). In-person enrollment takes longer but can be useful if you have questions or need help with documents.

What happens if you miss the important date

If you do not enroll during your seven-month Initial Enrollment Period, you can only sign up during the General Enrollment Period, which runs January 1 to March 31 each year. Coverage begins July 1 of that year. This means if you miss your Initial Enrollment Period in September and do not sign up until February, there is a gap of five months with no Medicare coverage, and you will owe a permanent penalty.

The penalty applies to Part B only. For every 12 months you were may be able to access but did not enroll, your Part B premium increases by 10 percent. If you were may be able to access for three years before signing up, your premium is 30 percent higher than the standard rate, and that surcharge stays on your bill for as long as you have Part B. There is no way to remove it.

The only exception to this penalty is if you had employer coverage or other may have access to coverage during the time you were not enrolled in Medicare. You must be able to prove this coverage with documents from your employer or plan.

Special situations: working past 65, part-time work, and self-employment

If you work past 65 and your employer has 20 or more employees, your employer plan is primary and Medicare is secondary. You can delay Part B without penalty. If your employer has fewer than 20 employees, Medicare is primary. You should still enroll in Part B to avoid penalties, even though Medicare will be the secondary payer.

Part-time work counts the same way: if your employer offers health insurance and you are enrolled in it, you can delay Medicare Part B. Self-employed people do not have employer coverage, so they cannot use this exception. If you are self-employed at 65, you should enroll in Medicare during your Initial Enrollment Period or face a penalty.

If you are still working but your employer does not offer health insurance, you must enroll in Medicare during your Initial Enrollment Period or pay a penalty. Working does not exempt you from enrollment if you do not have employer coverage.

Frequently Asked Questions

What if I turn 65 while I am still covered by my employer's health plan?

You can delay Part B without penalty as long as you notify Medicare that you have employer coverage during your Initial Enrollment Period. Once you leave the job or lose that coverage, you have eight months to sign up for Part B without penalty. If you do not notify Medicare of your employer coverage now, the penalty clock may start even though you are covered.

Can I sign up for Medicare before I turn 65?

No. Your Initial Enrollment Period does not open until three months before the month you turn 65. If you try to sign up earlier, the system will reject your process. You must wait until that three-month window opens.

Do I have to take Part D (prescription drug coverage) during my Initial Enrollment Period?

Part D is optional, but if you do not enroll when you first become may be able to access and later want it, you pay a permanent penalty. The penalty is 1 percent of the national average Part D premium for each month you were may be able to access but did not enroll. If you do not take any prescription drugs, you can skip Part D without penalty as long as you enroll later if your situation changes.

What if I am not a U.S. citizen?

You must be a U.S. citizen or a lawful permanent resident (green card holder) who has lived in the United States for at least five consecutive years to enroll in Medicare. If you are not yet a permanent resident, you cannot sign up. If you become a permanent resident after 65, your Initial Enrollment Period begins the month you become may be able to access, not the month you turn 65.

Can I change my mind after I sign up?

Yes, but only during specific windows. You have until the end of the month after you enroll to cancel and restart your enrollment. After that, you can only make changes during the Annual Enrollment Period (October 15 to December 7 each year) or if you experience a may have access to life event like losing employer coverage.