Medicare Part A vs Part B: A Simple Guide for Seniors

Why Understanding Medicare Part A vs Part B Matters More Than You Think

Here’s a fact that catches most people off guard: nearly 1 in 4 Medicare beneficiaries say they don’t fully understand their coverage, according to a Kaiser Family Foundation survey. If you’ve ever felt confused about the difference between Medicare Part A vs Part B, you’re far from alone.

And that confusion isn’t just frustrating — it can be expensive. Choosing the wrong time to enroll or misunderstanding what’s covered could leave you with unexpected hospital bills or monthly penalties that last for life.

The good news? Once someone breaks it down in plain English, Medicare actually makes a lot of sense. That’s exactly what we’re going to do right here.

In this guide, we’ll walk through what Part A covers, what Part B covers, what each one costs, and the key enrollment details you need to know. By the end, you’ll feel confident about your coverage — and know exactly where to turn if you have questions. Let’s get started.

What Is Medicare Part A? (Hospital Insurance)

Think of Medicare Part A as your hospital insurance. It’s the part of Medicare that kicks in when you need serious, inpatient medical care. If you’re admitted to a hospital, Part A is working for you.

Here’s what Medicare Part A typically covers:

1. Inpatient hospital stays — This includes a semi-private room, meals, nursing care, medications administered during your stay, and other hospital services.
2. Skilled nursing facility (SNF) care — If you need rehabilitative care after a qualifying hospital stay of at least 3 days, Part A covers up to 100 days in a skilled nursing facility.
3. Home health care — Part-time or intermittent skilled nursing care and therapy services in your home, if you’re homebound and meet specific criteria.
4. Hospice care — Comfort care for terminally ill patients, including pain management, counseling, and respite care for caregivers.
5. Inpatient care in a religious nonmedical health care institution — If this applies to your beliefs.

Important: Part A does not cover long-term custodial care in a nursing home (like help with bathing or dressing when no skilled medical need exists). This is one of the biggest misconceptions — and one of the costliest surprises — for seniors and their families.

What Is Medicare Part B? (Medical Insurance)

If Part A is your hospital coverage, Part B is your doctor and outpatient coverage. It handles the medical care you receive outside of a hospital admission — which, for most of us, is the majority of our healthcare.

Medicare Part B typically covers:

1. Doctor visits and office appointments — Including specialists like cardiologists, dermatologists, and orthopedists.
2. Outpatient procedures and surgeries — Anything done at a hospital or surgical center where you go home the same day.
3. Preventive services — Annual wellness visits, flu shots, mammograms, colonoscopies, diabetes screenings, and cardiovascular screenings. Many of these have no copay or deductible.
4. Durable medical equipment (DME) — Items like wheelchairs, walkers, hospital beds for home use, and oxygen equipment.
5. Ambulance services — When medically necessary transportation is required.
6. Mental health services — Outpatient therapy, psychiatric evaluations, and certain substance abuse treatments.
7. Lab tests and diagnostic imaging — Blood work, X-rays, MRIs, CT scans, and more.

One thing Part B does not cover well: routine dental, vision, and hearing care. These are gaps that many seniors fill with a Medicare Advantage plan or a standalone supplemental policy. You can explore more options in our Medicare Benefits Hub.

How Much Do Part A and Part B Cost?

This is where a lot of people get pleasantly surprised — and then a little confused. Let’s clear it up.

Medicare Part A Costs (2024)

Most people pay $0 in monthly premiums for Part A. You qualify for premium-free Part A if you (or your spouse) paid Medicare taxes for at least 40 quarters (10 years) during your working life. According to the Centers for Medicare & Medicaid Services (CMS), about 99% of Medicare beneficiaries qualify for premium-free Part A.

However, Part A does have other costs:

• Hospital deductible: $1,632 per benefit period in 2024. A benefit period starts when you’re admitted and ends when you’ve been out of the hospital or skilled nursing facility for 60 consecutive days.
• Days 1–60: $0 coinsurance after meeting the deductible.
• Days 61–90: $408 per day coinsurance.
• Lifetime reserve days (91+): $816 per day. You only get 60 of these in your lifetime.

Medicare Part B Costs (2024)

Unlike Part A, Part B has a monthly premium that everyone pays. The standard premium for 2024 is $174.70 per month. If your income is higher (above $103,000 for individuals or $206,000 for joint filers), you’ll pay more due to the Income-Related Monthly Adjustment Amount (IRMAA).

Other Part B costs include:

• Annual deductible: $240 in 2024.
• Coinsurance: After the deductible, you typically pay 20% of the Medicare-approved amount for most services.

That 20% coinsurance has no annual cap — which is why many seniors choose a Medigap (Medicare Supplement) policy to protect against large out-of-pocket expenses.

When and How to Enroll in Part A and Part B

Getting the timing right is critical. Enroll too late, and you could face permanent penalties that increase your premiums for life.

Your Initial Enrollment Period (IEP)

This is a 7-month window surrounding your 65th birthday: it starts 3 months before your birthday month, includes your birthday month, and extends 3 months after. During this time, you can sign up for both Part A and Part B.

Pro tip: If you’re already receiving Social Security benefits before age 65, you’ll be enrolled in Part A and Part B automatically. Your Medicare card will arrive in the mail about 3 months before you turn 65.

What If You’re Still Working at 65?

If you have employer coverage through a company with 20 or more employees, you can generally delay Part B enrollment without penalty. When you retire (or lose that employer coverage), you’ll get a Special Enrollment Period (SEP) — 8 months to sign up for Part B.

Don’t miss this window. If you do, you’ll have to wait until the General Enrollment Period (January 1 – March 31 each year), and your coverage won’t start until July. Plus, you’ll face a late enrollment penalty of 10% added to your Part B premium for every 12-month period you could’ve had Part B but didn’t. That penalty is permanent.

Part A Late Enrollment Penalty

If you don’t qualify for premium-free Part A, there’s also a late enrollment penalty: your premium can increase by 10% and you may have to pay the higher amount for twice the number of years you delayed.

To avoid costly mistakes, we recommend you download our free Medicare checklist so you have every important deadline in one easy-to-read guide.

Part A vs Part B: A Quick Side-by-Side Comparison

Here’s a simple summary to help you see the differences at a glance:

• Part A — What it covers: Hospital stays, skilled nursing, hospice, home health care
• Part B — What it covers: Doctor visits, outpatient care, preventive services, medical equipment
• Part A — Monthly premium: $0 for most people
• Part B — Monthly premium: $174.70/month (standard, 2024)
• Part A — Deductible: $1,632 per benefit period
• Part B — Deductible: $240 per year
• Part A — Coinsurance: $0 for days 1–60, then daily rates apply
• Part B — Coinsurance: 20% of Medicare-approved amounts (no cap)

Remember: You need both Part A and Part B to have complete Original Medicare coverage. One without the other leaves significant gaps.

Common Questions Seniors Ask About Part A and Part B

“Can I have Part A without Part B?”
Yes, you can enroll in Part A only. Some people do this if they have employer coverage that handles outpatient care. However, once you lose that employer coverage, sign up for Part B promptly to avoid penalties.

“Do I need anything beyond Part A and Part B?”
Most seniors benefit from additional coverage. Original Medicare doesn’t include prescription drug coverage (that’s Part D), and it doesn’t cap your out-of-pocket spending. Many people add a Part D plan and a Medigap policy — or choose a Medicare Advantage plan (Part C) that bundles everything. Visit our Medicare blog for detailed guides on all these options.

“What if I made a mistake with my enrollment?”
Don’t panic. There may be options depending on your situation. The Medicare & Medicaid Services hotline at 1-800-MEDICARE (1-800-633-4227) can help you sort things out, and your State Health Insurance Assistance Program (SHIP) offers free counseling.

Your Next Step: Get Confident About Your Medicare

Understanding the difference between Medicare Part A and Part B is one of the most important things you can do to protect your health and your wallet in retirement. Now that you know what each part covers, what it costs, and when to enroll, you’re already ahead of millions of Americans who never take the time to learn.

But knowledge is only powerful if you act on it. Review your current coverage, mark your enrollment deadlines, and make sure you’re not leaving benefits — or money — on the table.