In January 2011, baby boomers started turning 65. Since then,10,000 baby boomers are turning 65 every single day. And… this will continue until 2030.

Do You Have to Sign Up for Medicare?

This is an important question because if you don’t sign up for Medicare when you’re supposed to, you could end up paying a late enrollment penalty—and in some cases, that penalty can last for as long as you have Medicare.

So, do you have to sign up for Medicare?

Not necessarily.

Whether you need to enroll in Medicare when you turn 65 depends on your circumstances, including whether you are still working, what type of health insurance you have, and whether that coverage is based on your current employment.

The important thing is to understand the rules before you decide to delay Medicare.

Let’s take a look at who needs to sign up, who may be able to wait, and what can happen if you don’t enroll when you’re supposed to.

Do You Have to Sign Up for Medicare If You Are Still Working?

If you are still working when you turn 65 and you have health insurance through your or your spouse’s current employer, you may be able to delay Medicare Part B without paying a late enrollment penalty.

However, there is an important distinction based on the size of the employer.

If the employer has 20 or more employees, the employer group health plan generally pays first and Medicare pays second.

If the employer has fewer than 20 employees, Medicare generally pays first and the employer plan may pay second. In that situation, failing to enroll in Medicare when you’re eligible could leave you with unexpected gaps in coverage.

There are exceptions to these general rules, so you should always check with your employer’s benefits administrator before deciding whether to delay Medicare. Medicare recommends asking your employer how your coverage works with Medicare and whether you need to enroll in Part A and Part B.

So, what should you do if you’re still working?

Don’t simply assume that you can wait because you have insurance through work.

Ask your employer or human resources department:

• Is my health insurance based on my current employment?
• Does my employer’s plan pay first or does Medicare pay first?
• Do I need to enroll in Medicare Part A?
• Do I need to enroll in Medicare Part B?
• Is my prescription drug coverage considered creditable coverage for Part D?

Getting these answers before you turn 65 can help you avoid a very expensive mistake.

What If You Are Already Receiving Social Security?

If you are already receiving Social Security benefits when you become eligible for Medicare, you may be automatically enrolled in Medicare Part A and Part B.

If you don’t want Part B because you have qualifying coverage through current employment, you generally have the option to decline Part B.

The important thing is to understand why you are delaying Part B and make sure your existing coverage qualifies you to do so.

Don’t assume that simply having health insurance means you can safely decline Medicare Part B.

What Happens If You Don’t Have Employer Coverage?

If you aren’t covered by a qualifying employer health plan when you become eligible for Medicare, you generally should enroll in Medicare Part A and Part B during your Initial Enrollment Period.

For most people, the Initial Enrollment Period begins three months before the month they turn 65 and ends three months after the month they turn 65.

If you don’t enroll in Part B when you’re first eligible and you don’t qualify for a Special Enrollment Period, you may have to pay a late enrollment penalty for as long as you have Part B.

How much is the Part B late enrollment penalty?

The Part B late enrollment penalty is generally 10% of the standard Part B premium for each full 12-month period you could have had Part B but didn’t enroll.

For example, if you waited two full years to enroll in Part B and didn’t qualify for a Special Enrollment Period, your Part B premium would generally include a 20% late enrollment penalty.

In 2026, the standard Part B premium is $202.90 per month, although some people pay more because of income-related adjustments.

And remember, the Part B late enrollment penalty isn’t a one-time fee. It is added to your monthly Part B premium for as long as you have Part B.

Be Careful With COBRA and Retiree Coverage

One of the biggest Medicare mistakes I see involves people who retire from a job and assume they can simply continue their employer coverage through COBRA and worry about Medicare later.

That’s generally not a good strategy.

COBRA is not considered coverage based on current employment for purposes of the Part B Special Enrollment Period. Your eight-month Special Enrollment Period for Part B generally begins when you stop working or lose your qualifying employer coverage—even if you choose COBRA.

Retiree coverage also does not work the same way as coverage from a current employer. Your retiree plan may require you to have Medicare Part A and Part B before it will pay as expected.

So don’t assume that COBRA or retiree coverage allows you to delay Medicare.

Check with your benefits administrator before making a decision.

What About VA Coverage?

VA coverage can be confusing because there are different rules for medical coverage and prescription drug coverage.

VA coverage does not count as coverage from current employment for purposes of delaying Part B without penalty.

However, VA prescription drug coverage can qualify as creditable prescription drug coverage for Part D.

That’s an important distinction.

If you have VA coverage, talk with the VA and Medicare about how your coverage works before deciding whether to enroll.

What Are the Four Parts of Medicare?

There are four parts of Medicare:

• Part A – Hospital Insurance
• Part B – Medical Insurance
• Part C – Medicare Advantage
• Part D – Prescription Drug Coverage

It’s also important not to confuse the Parts of Medicare with Medigap plans, which also use letters such as Plan G, Plan K, Plan N, and others.

Medicare Part A

Most people think of Part A as the part of Medicare that covers hospital care.

It also covers other services, including:

• Inpatient hospital care
• Skilled nursing facility care
• Hospice care
• Some home health care

Most people qualify for premium-free Part A because they or their spouse paid Medicare taxes long enough while working.

Medicare Part B

Part B is the part of Medicare that generally covers doctor visits and other medically necessary outpatient services.

It also covers things such as:

• Doctor services
• Outpatient surgery
• Lab tests
• Durable medical equipment
• Certain preventive services
• Many medically necessary services and supplies

Part B has a monthly premium. In 2026, the standard Part B premium is $202.90 per month, although people with higher incomes may pay more.

Part B is technically optional, but that doesn’t mean you should automatically decline it.

If you don’t have qualifying coverage that allows you to delay Part B, failing to enroll when you’re first eligible can result in a lifetime late enrollment penalty.

Do You Have to Sign Up for Medicare Part D?

Part D is Medicare’s prescription drug coverage.

And yes, Part D has its own late enrollment penalty.

You generally need to enroll in Part D when you first become eligible unless you have other creditable prescription drug coverage.

Creditable prescription drug coverage is coverage that is expected to pay, on average, at least as much as standard Medicare prescription drug coverage. This can include certain employer or union plans, TRICARE, VA drug coverage, and other qualifying coverage.

If you go 63 days or more without Part D or other creditable prescription drug coverage after becoming eligible, you may have to pay a Part D late enrollment penalty if you enroll later.

How much is the Part D penalty?

The Part D late enrollment penalty is calculated by multiplying:

1% × the national base beneficiary premium × the number of full months you went without creditable drug coverage.

In 2026, the national base beneficiary premium is $38.99.

For example, if you went 14 full months without creditable prescription drug coverage, your penalty would generally be 14% of $38.99, or approximately $5.50 per month in 2026.

The penalty is added to your Part D premium for as long as you have Medicare drug coverage.

So even if you don’t take many prescription medications right now, it’s important to understand the Part D rules.

One important change: The Medicare Part D “donut hole” is gone.

If you’ve read older Medicare articles, you may have heard about the Part D coverage gap, commonly called the “donut hole.”

That is no longer how Part D works.

Beginning in 2025, Medicare prescription drug coverage has an annual out-of-pocket limit for covered Part D drugs. In 2026, that limit is $2,100. Once you reach that amount in covered out-of-pocket Part D costs, you pay nothing for covered Part D drugs for the rest of the calendar year.

Do You Have to Sign Up for Medicare Part C?

No. Part C, also called Medicare Advantage, is optional.

Medicare Advantage plans are offered by private insurance companies approved by Medicare.

When you enroll in Medicare Advantage, the plan provides your Medicare-covered Part A and Part B benefits. You still have Medicare, but you receive your Medicare-covered benefits through the Medicare Advantage plan rather than directly through Original Medicare.

You must have both Part A and Part B to join a Medicare Advantage plan, and you generally continue paying your Part B premium while enrolled.

Most Medicare Advantage plans include Part D prescription drug coverage. These are commonly called MAPD plans — Medicare Advantage Prescription Drug plans.

One feature many people appreciate about Medicare Advantage is that plans have an annual maximum out-of-pocket limit for covered Medicare services. Once you reach the plan’s limit, the plan pays 100% of covered services for the remainder of the calendar year.

However, Medicare Advantage plans can have networks, copayments, coinsurance, prior authorization requirements, and other plan-specific rules.

That’s why it’s important to compare the details of the individual plans available in your area.

What If You Prefer Original Medicare?

Some people prefer to keep Original Medicare and purchase a Medicare Supplement Insurance plan, also called a Medigap plan.

Medigap plans help pay some of the costs that Original Medicare doesn’t fully cover, such as certain deductibles and coinsurance.

If you have Original Medicare and a Medigap plan, you’ll generally also need separate prescription drug coverage if you want Part D coverage.

Medigap plans can be appealing to people who want to use any doctor or other provider that accepts Medicare, rather than being limited to a Medicare Advantage plan’s network. However, Medigap plans have monthly premiums, and you’ll generally also pay a separate Part D premium if you enroll in a Medicare drug plan.

You can find more information about Medigap plans here.

So, Do You Have to Sign Up for Medicare?

Sometimes yes, and sometimes no.

If you’re still working and have qualifying coverage through your or your spouse’s current employer, you may be able to delay Part B without a late enrollment penalty.

But if you don’t have qualifying coverage, delaying Medicare could result in:

• A Part B late enrollment penalty
• A Part D late enrollment penalty
• Gaps in your health coverage
• Unexpected medical bills

And sometimes, even when you can delay Medicare, it may be worth comparing your options.

For example, depending on your employer’s premiums, deductibles, copayments, prescription costs, and other benefits, Medicare coverage could potentially be less expensive than your current employer plan.

But don’t compare just the monthly premiums.

You’ll want to compare the total cost of coverage, including:

• Monthly premiums
• Deductibles
• Copayments
• Coinsurance
• Prescription drug costs
• Maximum out-of-pocket expenses
• Provider networks
• Coverage for your specific medications

Your prescription coverage deserves particular attention because Medicare Part D works differently from most employer drug plans.

The Bottom Line

Do you have to sign up for Medicare when you turn 65?

The answer depends on your specific situation.

If you’re still working and have health insurance through current employment, you may be able to delay Medicare Part B without a penalty.

If you don’t have qualifying coverage, enrolling when you’re first eligible is generally the safest way to avoid late enrollment penalties and potential gaps in coverage.

And don’t forget about Part D prescription drug coverage. Even if you don’t take many medications today, going without creditable drug coverage for 63 days or more after you’re eligible can result in a permanent Part D late enrollment penalty later.

If you’re approaching age 65, retiring, losing employer coverage, or simply aren’t sure whether you need to enroll in Medicare, don’t guess.

Check your specific situation before making a decision.

You can also find more information about Medicare directly at Medicare.gov.

We also have free Medicare classes that you can take online anytime. Just go to Free Online Medicare Classes to sign up.

We do not offer every plan available in your area. Any information we provide is limited to those plans we do offer in your area. Please contact Medicare.gov or 1-800-MEDICARE to get information on all of your options.