What Is The Difference Between Medicare Part A And Part B

Part A is hospital insurance that covers inpatient stays and skilled nursing, while Part B is medical insurance that covers doctor visits, outpatient care, and preventive services.

What Medicare Part A vs B Covers: Hospital Insurance

Part A pays for care you receive as a *patient admitted to a medical facility*, not care you receive as a walk-in or an outpatient. That includes a semi-private room, meals, general nursing, medications administered during your stay, and use of the operating room or intensive care unit. It also covers a stay in a skilled nursing facility (SNF) *after* a qualifying inpatient stay of at least three midnights. Coverage lasts for up to 100 days per benefit period, and only if you need daily skilled care like physical therapy or wound care that a nurse must provide.

Beyond those two big settings, Part A covers hospice care for terminal illness, including pain management and counseling. It also covers home health care like part-time skilled nursing or home health aide visits, but only if you’re homebound and your doctor certifies the need. What Part A does *not* cover is any care you receive while not formally admitted: observation status in a facility bed, a doctor’s consultation in the emergency room, or any outpatient surgery. Those fall under Part B, which is why the two parts work as a pair.

What Part B Actually Covers

Part B is the medical insurance half, and it covers the services you typically think of as “seeing a doctor.” That includes office visits, specialist consultations, lab tests like blood work and urine analysis, X-rays and MRIs, and preventive screenings like mammograms, colonoscopies, and annual wellness visits. It also covers durable medical equipment (DME) such as wheelchairs, walkers, inpatient beds, and continuous positive airway pressure (CPAP) machines. Coverage applies only if a doctor prescribes them and you use a Medicare-approved supplier.

Mental health care is also under Part B, both outpatient therapy and partial hospitalization for more intensive treatment. Ambulance services are covered too, but only when ground or air transport is medically necessary and other transportation would endanger your health. What Part B does *not* cover is routine dental care, eye exams for glasses, hearing aids, or most long-term care. Those are separate policies you’d buy on your own. If you’re sitting in a clinic, a lab, or a doctor’s office, the bill almost always goes to Part B first.

The Mistake People Make About Costs

The most common error is assuming Part A is always free. For most people who paid Medicare payroll taxes for at least 10 years, Part A has a premium that starts at $0 per month, but that’s not the whole story. The Centers for Medicare & Medicaid Services (CMS) sets this figure annually, and you should verify your exact amount at Medicare.gov. If you didn’t work that long, you’ll pay a monthly premium for Part A, and *everyone* with Part A pays a separate deductible per benefit period before coverage kicks in. CMS publishes the inpatient deductible each year; it falls within a band that can reach roughly $1,700, and it renews every time you’re admitted to a care facility, even if it’s the same month. Check the official CMS announcement for the current number.

Part B, meanwhile, always has a monthly premium. CMS sets a standard amount near $185 for most people, though higher incomes pay more through income-related monthly adjustment amounts (IRMAA). Part B also has its own annual deductible, which CMS fixes in a range around $260, and then a 20% coinsurance on most services after that. The mistake people make is comparing the Part A premium floor to the Part B standard premium and thinking Part A is the better deal. It’s not. Part B covers the care you actually use, and skipping it means you pay 100% of every doctor bill, lab test, and ambulance ride out of pocket. The total **Medicare cost in 2025** for most people is the Part B premium plus the Part B deductible, and that’s before you factor in the Part A deductible if you’re admitted. Always confirm the year’s exact rates through the official Medicare source.

When You Need Both Parts

If you enroll only in Part A, you’re covered for an inpatient stay but you’ll face a 100% bill for the doctor who treats you there, the anesthesiologist, the radiologist reading your X-ray, and any lab work done during your stay. Those are Part B services. If you enroll only in Part B, you’re covered for office visits but you’ll pay the full cost of any inpatient stay out of pocket. That includes the deductible and the daily coinsurance that kicks in after 60 days. Original Medicare is the only national health program where Part A and Part B are legally required to work as a single, indivisible safety net: Part A covers the bed and the nursing, Part B covers the doctors and the tests, and neither piece functions as a complete policy on its own.

The coverage gaps you face with only one part are not minor. With Part A only, a simple outpatient procedure like a colonoscopy (covered under Part B) costs you thousands. With Part B only, a broken hip requiring surgery and a three-night inpatient stay leaves you with a five-figure bill. That’s why the standard advice is to enroll in both when you first become eligible. It is also the safest way to **enroll in Medicare without a penalty**. Delaying Part B after 65 triggers a late enrollment penalty that adds 10% to your premium for every 12-month period you waited. If you’re comparing plans, you’ll want to **compare Medicare advantage plans against original Medicare** to see if a private plan bundles A and B with extra benefits. The underlying rule remains the same: you need both parts to avoid catastrophic gaps. For a fuller look at coverage decisions, the **healthcare & medicare** hub is the place to start, but the core takeaway is simple. Part A for the facility, Part B for the doctor, and both for your health.

Frequently Asked Questions

Can I delay Part B if I’m still working at 65?

Yes, but only if you have group health coverage through your or your spouse’s current employer, and only if that employer has 20 or more employees. You’ll get a special enrollment period (SEP) to sign up for Part B without a penalty when that coverage ends or you retire.

What happens to Part A and B if I move to another state?

Original Medicare works nationwide, so your Part A and Part B coverage follows you wherever you live in the United States. You just need to update your address with Social Security so you receive your bills and notices.

Does Part A or B cover a yearly physical?

Part B covers a one-time “Welcome to Medicare” preventive visit in your first 12 months, plus an annual wellness visit every year after that. A full physical with blood tests and a comprehensive exam is not covered by either part, you’d pay for that separately.