If you’re planning to work past age 65, there are several rules with Medicare to be aware of.
If you make a mistake here, you could potentially find yourself subject to permanent penalties on your Medicare premiums.
In this article, we’ll go over whether or not you should enroll in Medicare if you’re still working, when you can delay enrolling in Medicare, how and when to enroll in Medicare if you delay, and what happens if you miss your enrollment periods.
Short Answer: Is It Mandatory to Enroll in Medicare at 65 If You’re Still Working?
No, it is not mandatory to enroll in Medicare at 65, whether you’re still working or not.
However, if you delay enrolling in Medicare past age 65 and you don’t qualify for a Special Enrollment Period, you may incur late enrollment penalties when you sign up.
If you are still working, you may qualify for a Special Enrollment Period depending on how many employees your company has.
Should You Enroll in Medicare At Age 65 If You’re Working?
While it isn’t mandatory to enroll in Medicare at age 65, getting a permanent late enrollment penalty can be expensive. That’s why it’s important to know when you can and can’t delay enrollment without incurring these penalties.
When You May Need to Enroll in Medicare
Here are some instances where you may want to enroll in Medicare once you turn 65:
- You’re unemployed/retired.
If you’re unemployed or retired, you generally want to enroll in Medicare as soon as you can to avoid penalties.
- You’re employed, but your company has fewer than 20 employees.
If your company has fewer than 20 employees, Medicare usually considers your employer-sponsored health plan as a “small group health plan.”
As a result, when you turn 65, Medicare becomes the primary payor, while your employer-sponsored insurance will likely pay second to Medicare.
This is a fancy way to say that, in this situation, Medicare is typically going to expect you to enroll in order to not get penalties.
That’s why, if your company has fewer than 20 employees, generally you may want to enroll in Medicare once you turn 65.
- You have noncreditable coverage from elsewhere.
If you have retirement coverage from your employer, COBRA coverage, VA benefits, an Affordable Care Act (ACA) plan, TRICARE (while not on active duty), or are employed but don’t have health coverage, you typically would enroll in Medicare to avoid penalties.
These health insurance plans generally pay second to Medicare when you turn 65. If you aren’t enrolled in Medicare, you may have to pay Medicare’s portion yourself.
When You May Not Want to Enroll in Medicare
If you’re still working and your employer has 20 or more employees, you can generally delay enrolling in Medicare until you retire or you lose your coverage without receiving penalties.
This is because Medicare considers companies with 20 or more employees as “large group coverage.” If you have large group coverage, your health insurance usually won’t become secondary to Medicare once you turn 65, so you can decide if you want to stick to your employer-sponsored plan or switch to Medicare.
Here are some reasons you may want to consider staying with your employer’s plan:
- Your employer plan is a better fit for you.
Some people assume that Medicare is always better than their employer-sponsored plan. However, this is not always the case.
Medicare is not free. The base premium for Medicare Part B is $202.90/month in 2026. Most people also enroll in either a Medicare Supplement or Medicare Advantage Plan, which also have separate premiums.
That’s why it’s important to compare your current coverage to what Medicare has to offer. Compare plan premiums, out-of-pocket costs, what’s covered, networks of doctors and hospitals, and all coverage details.
This will help you determine whether staying with your employer-sponsored plan is better for you than switching to Medicare.
- Your employer plan covers your spouse and dependents.
Medicare only covers you, not your spouse or dependents. If your employer-sponsored plan covers your spouse or your dependents, you may choose to delay Medicare and stay on your current plan so your loved ones won’t lose their coverage.
- You want to continue contributing to your Health Savings Account (HSA).
If you have a Health Savings Account (HSA) that you want to continue contributing to, you may want to delay enrolling in Medicare.
This is because any contributions you make to an HSA while enrolled in Medicare may be subject to tax penalties.
How To Enroll in Medicare If You Delay
Once you lose your employer-sponsored coverage, you’ll typically get a Special Enrollment Period (SEP) to enroll in Medicare.
This SEP lasts 8 months, starting when you retire or lose your health coverage.
To enroll during this period, you’ll fill out the CMS-L564 and CMS-40B forms.
- CMS-L564 is filled out by both you and your employer. This proves to Medicare that you had creditable coverage from elsewhere during the months you could have had Medicare, and will prevent you from incurring late enrollment penalties.
- CMS-40B is a Medicare enrollment form used for Special Enrollment Periods. You can also write down when you want your Medicare coverage to start in this form.
If you already have Medicare Part A, simply submit these forms to your local Social Security office to enroll in Medicare Part B.
If you haven’t enrolled in Medicare Part A yet, you’ll first need to enroll in Medicare online or by calling Social Security at +1 800-772-1213 (TTY: +1 800-325-0778).
What Happens If You Don’t Enroll in Time?
If you fail to enroll in Medicare during your Initial Enrollment Period (IEP) or within your Special Enrollment Period (SEP), you may incur late enrollment penalties.
Note: Your IEP typically starts three months before the month you turn 65, runs through the month you turn 65, and ends three months after the month you turn 65.
The late enrollment penalty for Medicare Part B is an extra 10% added to your premium for every year that you delay.
Meanwhile, there is also a late enrollment penalty for Medicare Part D, the prescription drug part of Medicare. This penalty is an extra 1% of the national base beneficiary premium for Medicare Part D for every month that you delay.
That’s why it’s critical to know when your enrollment periods are and avoid missing them.
Still Have Questions About Medicare?
Medicare’s rules about working past 65 can be confusing.
However, now that you know if you need to sign up, what your enrollment windows are, and what happens if you don’t enroll, you should have a solid plan for working past age 65.
If you still have questions, you can always contact our team of licensed insurance agents at +1 877-360-6565 (TTY: 711).
Or, if you’d like to learn more about how Medicare works, what the different parts and plans are, and want to have a comprehensive understanding of Medicare, then sign up for our free Medicare workshop below.
Calvin Bagley is the founder of PlanFit, The Medicare Store, and Nuvo Health. He and his team have helped over 60,000 people navigate Medicare options, and he’s a nationally recognized speaker in the Medicare industry. Most importantly, he’s someone who believes every American deserves clear, honest information without pressure.
