Medicare is a federal program that provides health insurance to Americans 65 and older, as well as to certain younger individuals with disabilities. However, the rules for signing up can be confusing or even overwhelming — especially when it comes to deadlines, penalties and how employment status affects your options.

To help clarify the process, here are answers to 10 common questions about applying for Medicare.

1. When Do I Need to Apply?

Most people become eligible for Medicare at 65. You generally have a seven-month initial enrollment period, unless you qualify for an exception. This period starts three months before your 65th birthday, includes your birthday month, and extends three months afterward.

For example, if you turn 65 in June, your enrollment window runs from March 1 through September 30. Applying early helps avoid gaps in coverage and potential penalties.

2. How Long Does the Application Process Take?

The actual application process through the Social Security Administration (SSA) is relatively quick — you may be able to complete it online in about 10 to 20 minutes. In many cases, you may receive your Medicare card in the mail within three weeks after approval.

That said, processing times can vary. According to government figures, approximately 11,000 people turn 65 per day, so SSA employees can get busy! Starting your application a few months before coverage is needed will give you peace of mind and reduce the risk of delays.

3. What Happens If I Miss the Enrollment Deadline?

If you don’t enroll in Medicare on time and don’t qualify for an exception, you may face late enrollment penalties. These penalties can add up, so staying on top of deadlines is essential.

4. What Do Medicare Parts A, B, C and D Cover?

An easy trick for differentiating the different types of Medicare coverage is to remember this list:

• A = admission (hospital and other facilities),
• B = basic medical (doctor visits, outpatient),
• C = combined (all-in-one private plan), and
• D = drugs (prescriptions).

More specifically, Part A is hospital insurance. It covers inpatient hospital care, a skilled nursing facility after a qualifying hospital stay, hospice care and limited home health care.

Part B is medical insurance that covers doctors’ visits, outpatient care, lab tests, X-rays, certain medical equipment (such as a wheelchair or walker), and some home health care not covered under Part A. Parts A and B are the core components of Medicare, often called original Medicare. They’re not optional plans you “shop for” — they’re the standard federal coverage you enroll in.

Part C is an alternate way to receive Medicare benefits. Instead of getting Part A and Part B coverage directly through the federal government, you can choose to get them through a private insurance company that contracts with Medicare. These plans are called Medicare Advantage Plans. They may include benefits that Medicare Part B doesn’t, such as vision and dental coverage and gym memberships. However, your choice of doctors and facilities can be limited.

Part D is the part of Medicare that provides prescription drug coverage. Unlike Part A and Part B, which are administered directly by the federal government, Part D is offered through private insurance companies that contract with Medicare.

5. What’s the Difference Between a Medicare Advantage Plan and a Medicare Supplement Plan?

You can choose to enhance Medicare Part A and B coverage with a Medicare Supplement Plan. This is one of the biggest points of confusion. Both Medicare Advantage (Part C) and Medicare Supplement options help cover health care in retirement, but they work in different ways — and the plans can’t be combined.

A Medicare Supplement Plan (often referred to as Medigap) works in conjunction with Medicare Parts A and B to cover some or all deductibles, copayments and coinsurance. You buy it from a private insurance company. You can see any doctor or hospital that accepts Medicare nationwide. A Supplement Plan doesn’t include prescription drugs. You’ll need a standalone Part D plan for that.

There are standardized Supplement Plans, labeled A through N, with different options. However, they rarely include dental or vision benefits (you must buy them separately or pay out of pocket). Generally, the best time to enroll in a Supplement Plan is during an open enrollment period (the first 6 months after you’re 65 and enrolled in Part B). After that, underwriting can apply (with state exceptions).

6. How Much Does Coverage Cost?

You won’t pay anything for Part A if you or your spouse worked and paid Medicare taxes for at least 10 years. (If you’re not eligible for premium-free Part A, it can cost $285 or $518 a month in 2025, depending on your work history.)

There’s a monthly premium and an annual deductible for Part B coverage. For 2025, the standard premium is $185, and the annual deductible is $257. The premium and deductible amounts for 2026 haven’t been announced yet. Higher-income individuals must pay a surcharge in addition to the base premium for Part B coverage (see question 7 below).

The cost for Part C (Medicare Advantage) is more complicated. You must still pay the Part B premium (and Part A if you don’t get it premium-free). Some Advantage Plans charge an additional monthly premium, while others are free. You may have copayments or coinsurance when you use an Advantage Plan, and you generally must use doctors and hospitals within a provider’s network. Advantage Plans have an annual limit on out-of-pocket expenses for covered services — a benefit that Medicare Part A and B doesn’t provide (unless you add a Supplement Plan to cover cost sharing).

The monthly premium cost for Part D varies by plan, location and potentially your income. There’s a deductible set each year by the federal government. There are also copayments or coinsurance each time you fill a prescription. In 2025, out-of-pocket costs for covered Part D drugs are capped at $2,000. After that point, you pay $0 for covered drugs the rest of the year. This change was made by the Inflation Reduction Act of 2022.

If you choose a Medicare Supplement Plan, you’ll pay your Part B premium, plus a monthly premium for the supplement. You generally have more freedom of choice and coverage of deductibles. But premiums are often higher than Advantage Plan premiums. They vary by insurer and location.

7. What’s an IRMAA?

If your income is above a certain threshold, you may be required to pay an Income-Related Monthly Adjustment Amount (IRMAA). This is an extra charge that’s applied to Medicare Part B and Part D premiums. The SSA determines the IRMAA based on your tax return from two years prior.

For example, your 2025 Medicare premiums could be based on the modified adjusted gross income (MAGI) reported on your 2023 tax return. Because of this, strategic tax planning with your tax advisor may help you manage or potentially reduce IRMAA charges in advance of Medicare enrollment.

For 2025, the threshold for the IRMAA begins at 2023 MAGI of $106,000 for individuals ($212,000 for married couples who file jointly). If the IRS reports to the SSA that your income is above this amount, your monthly premium will be higher. Instead of paying $185 a month in 2025, you could pay up to $628.90 a month.

In the two years after you retire, you may have a much lower income than you did when you were working. In that case, there’s a way to ask for a reconsideration or appeal of your IRMAA. For example, let’s say you were working in 2023 and had a MAGI that year of $125,000. You turned 65 and retired earlier this year, and your MAGI for 2025 will only be $50,000. Assuming you’re single, you’re above the IRMAA threshold when you apply for Medicare in 2025.

You can fill out Form SSA-44, “Medicare Income-Related Monthly Adjustment Amount — Life Changing Event.” It’s a request to recalculate your IRMAA due to a loss-of-income event, such as retirement, divorce or the death of a spouse. If your appeal is accepted, your Part B and Part D premiums may be reduced going forward or even refunded retroactively, depending on the circumstances.

8. How Do I Pay for Medicare?

Paying for Medicare depends on which part of Medicare you enroll in and whether you’re already receiving Social Security. If you get Social Security (or Railroad Retirement) benefits, your premium is usually deducted directly from your monthly benefit.

If you’re not yet receiving Social Security, you’ll receive a bill quarterly. You can pay by check or money order by mail, through bank account deductions or by credit or debit card.

For a Part C Advantage Plan, you sometimes have to pay an additional monthly premium to the private insurer. Most will allow you to set up automatic payments or billing. The same is true with Supplement Plans. Part D premiums may be deducted from your Social Security (or Railroad Retirement) benefits, or you can pay the insurer directly.

9. Can I Keep Employer-Provided Health Insurance If I’m Still Employed After 65?

If you or your spouse is still working and you have employer-sponsored health coverage, you may not need to enroll in Medicare Part B during the seven-month initial enrollment period around your 65th birthday. Many people keep their employer coverage and delay Part B without penalty — as long as the employer has 20 or more employees, and the plan is considered “creditable coverage.” With smaller employers, or if you only have retiree coverage or COBRA, Medicare is primary at age 65, and failing to enroll in Part B can lead to coverage gaps and late penalties.

Note: Even if you don’t apply for Medicare Part B because you still have employer insurance, you may choose to apply for no-cost Medicare Part A during your initial enrollment window. However, if you’re actively contributing to a Health Savings Account (HSA), you should delay enrolling in Part A and coordinate the stop date for contributions. That’s because when you sign up for Part A after age 65, coverage is retroactive up to 6 months (but no earlier than your 65th birthday month), which can disqualify any HSA contributions made during that period.

Once you decide to apply for Medicare, you’ll need to submit Centers for Medicare and Medicaid Services (CMS) Form L564, “Request for Employment Information,” to the SSA. It’s completed by you and your employer (or former employer) and verifies that you had employer-provided group health plan coverage from the time you turned 65. This proof ensures you qualify for a “special enrollment period” and avoids the late enrollment penalty.

10. How Much Is the Late Enrollment Penalty?

If you don’t apply for Medicare during the seven-month initial enrollment period around your 65th birthday, you may incur late enrollment penalties, depending on which part of Medicare you delay. There’s no penalty if you sign up late for Part A and qualify for premium-free coverage.

However, if you don’t sign up for Part B when first eligible and you don’t have creditable coverage (such as employer insurance), you’ll pay a 10% increase in the monthly premium for each full 12-month period you should have had Part B but didn’t. The penalty lasts for as long as you have Part B — often for the rest of your life.

While Medicare Part D prescription drug coverage is technically optional, going without it can be costly. If you go 63 or more consecutive days without Part D or other creditable drug coverage, the penalty is 1% of the “national base beneficiary premium” per month you were uncovered. This amount is added to your monthly Part D premium and lasts for as long as you have Part D. In other words, you don’t have to sign up for Part D right away — but unless you have other qualifying drug coverage, delaying enrollment will lead to a permanent financial penalty.

Final Thoughts

Medicare enrollment involves more than just filling out a form. It’s a decision that affects your health care and retirement finances. By understanding deadlines, penalties and income-based costs, you’ll be better prepared to make smart choices. After you’re enrolled, there may be regular opportunities to adjust coverage.

The information in this article is meant to help with the enrollment process. Other rules and limits may apply. Because each situation is unique, it’s best to speak with an insurance advisor, your health care providers and your tax advisor to make the right choices for your situation.