Medicare Part A vs. Medicare Part B

Understanding the Two Parts of Original Medicare

When people say "Medicare," they usually mean Original Medicare, which consists of two distinct parts. Medicare Part A is hospital insurance — it covers inpatient hospital stays, skilled nursing facility care, hospice, and some home health services. Medicare Part B is medical insurance — it covers doctor visits, outpatient care, preventive services, medical equipment, and some home health services.

Together, Part A and Part B form the foundation of Medicare coverage. Most seniors are automatically enrolled in Part A when they turn 65 (if they are receiving Social Security), but Part B requires an active enrollment decision and a monthly premium. Understanding the differences between these two parts helps you plan for healthcare costs, avoid late enrollment penalties, and make informed choices about supplemental coverage like Medicare Advantage or Medigap.

Side-by-Side Comparison

Medicare Part A: Hospital Insurance in Detail

Medicare Part A is designed to cover the most expensive types of medical care: hospital stays and related institutional care. Here is what Part A covers and how costs work:

What Part A Covers

• Inpatient hospital care: Semi-private room, meals, nursing care, drugs administered during your stay, and other hospital services. This is the core of Part A coverage.
• Skilled nursing facility (SNF) care: Up to 100 days per benefit period following a qualifying 3-day hospital stay. Days 1–20 are fully covered; days 21–100 require a $209.50 daily copay in 2026.
• Hospice care: For terminally ill patients with a life expectancy of 6 months or less. Covers pain management, symptom relief, and counseling. Small copays may apply for drugs and respite care.
• Home health care: Part-time skilled nursing care, physical therapy, and other services if you are homebound and meet specific criteria.

Part A Cost Structure

Part A uses a "benefit period" system rather than a calendar year. A benefit period begins when you are admitted to a hospital and ends when you have been out of the hospital or skilled nursing facility for 60 consecutive days. If you are readmitted after 60 days, a new benefit period starts and you pay the deductible again.

This structure means you could potentially pay the $1,676 deductible multiple times in a single year if you have repeated hospitalizations. There is no out-of-pocket maximum for Part A, which is one reason many seniors purchase Medigap or Medicare Advantage plans for additional protection.

Medicare Part B: Medical Insurance in Detail

Medicare Part B covers a broad range of outpatient and preventive services that most seniors use regularly. It is arguably the part of Medicare that affects daily healthcare the most.

What Part B Covers

• Doctor and specialist visits: Office visits, consultations, and second opinions from Medicare-accepting physicians.
• Outpatient surgery and procedures: Ambulatory surgical center services, diagnostic tests, and outpatient hospital services.
• Preventive services: Annual wellness visits, flu shots, screenings for cancer, diabetes, cardiovascular disease, depression, and more — many at no cost to you.
• Lab tests and diagnostic imaging: Blood work, X-rays, CT scans, MRIs, and other imaging services.
• Durable medical equipment (DME): Wheelchairs, walkers, hospital beds, oxygen equipment, and certain other medical supplies.
• Mental health services: Outpatient therapy, psychiatrist visits, and partial hospitalization programs.
• Ambulance services: When medically necessary transportation is required.

Part B Cost Structure

After paying the $257 annual deductible, you typically pay 20% of the Medicare-approved amount for most services. There is no annual out-of-pocket maximum under Part B, which means your 20% coinsurance could add up significantly for expensive treatments like chemotherapy or major surgeries.

The standard Part B premium is $185.00 per month in 2026, deducted automatically from your Social Security check. Beneficiaries with higher incomes pay additional surcharges through the Income-Related Monthly Adjustment Amount (IRMAA), which can increase premiums to over $500 per month for the highest income brackets.

What Neither Part A Nor Part B Covers

Understanding the gaps in Original Medicare is just as important as understanding what is covered. Neither Part A nor Part B covers:

• Most prescription drugs: You need a separate Part D plan or Medicare Advantage plan with drug coverage.
• Routine dental care: Cleanings, fillings, dentures, and most dental procedures are not covered.
• Routine vision care: Eye exams for glasses and contact lenses are generally not covered.
• Hearing aids: Neither the devices nor fitting exams are covered.
• Long-term custodial care: Nursing home care that is primarily custodial (help with daily activities) rather than skilled medical care.
• Care outside the United States: With very limited exceptions.

These gaps are why many seniors supplement Original Medicare with a Medigap policy or Medicare Advantage plan, and why understanding the difference between Medicare and Medicaid is important for those who may qualify for additional assistance.

Which Is Right for You?

This is not an either-or decision for most people — the vast majority of seniors need and enroll in both Part A and Part B. The real decisions are:

• When to enroll in Part B: If you have employer-sponsored coverage (from your own or a spouse's current employer with 20+ employees), you can delay Part B without penalty. Otherwise, sign up during your Initial Enrollment Period to avoid lifelong late enrollment penalties.
• Whether to add supplemental coverage: Since neither Part A nor Part B has an out-of-pocket maximum, most financial advisors recommend adding either a Medigap policy or joining a Medicare Advantage plan.
• Whether you need Part D: Since prescription drugs are not covered by Part A or B, you should evaluate whether a standalone Part D plan or a Medicare Advantage plan with drug coverage is necessary.

Frequently Asked Questions