Medicare Part A covers hospital and inpatient care, while Part B covers doctor visits, outpatient services, and preventive care. Together, they form what’s called Original Medicare, and most people 65 and older are eligible for both. Here’s a detailed look at what each part pays for, what it costs, and the notable gaps you should know about.
What Part A Covers
Part A is hospital insurance. It pays for care you receive as an admitted inpatient, along with a few other categories of facility-based care. Covered inpatient hospital services include a semi-private room, meals, general nursing, medications administered during your stay, and other hospital services and supplies tied to your treatment.
Part A also covers stays in a skilled nursing facility, hospice care, and some home health services. The skilled nursing benefit has strict eligibility rules: you must first have a qualifying inpatient hospital stay of at least three consecutive days (observation hours don’t count, even if you’re at the hospital overnight). You then need to enter a Medicare-certified skilled nursing facility within 30 days of leaving the hospital and require daily skilled care like physical therapy or intravenous medications. Part A limits skilled nursing coverage to 100 days per benefit period.
Hospice care under Part A covers pain management, symptom relief, and support services for people with a terminal illness who choose comfort care over curative treatment.
What Part B Covers
Part B is medical insurance. It picks up two broad categories: medically necessary services (things your doctor orders to diagnose or treat a condition) and preventive services (care aimed at catching illness early or preventing it altogether).
On the medically necessary side, Part B covers doctor office visits, outpatient surgery, lab tests, diagnostic imaging, mental health and substance use treatment, and durable medical equipment like wheelchairs, walkers, and oxygen supplies prescribed for home use. Equipment qualifies for coverage if it’s durable enough for repeated use, serves a medical purpose, is primarily useful to someone who is sick or injured, and is expected to last at least three years.
Part B also covers ambulance services, second surgical opinions, and outpatient therapies including physical therapy, occupational therapy, and speech-language pathology.
Preventive Services at No Cost
One of the most valuable features of Part B is its preventive care benefit. You pay nothing for most preventive services when you see a provider who accepts Medicare assignment. The list is extensive:
- Cancer screenings: mammograms, colonoscopies, lung cancer screenings, prostate cancer screenings, and cervical and vaginal cancer screenings
- Cardiovascular care: cholesterol and lipid screenings, plus behavioral therapy for heart disease risk
- Diabetes: diabetes screenings, self-management training, medical nutrition therapy, and the Medicare Diabetes Prevention Program
- Vaccinations: flu shots, COVID-19 vaccines, pneumococcal shots, and hepatitis B shots
- Mental health: depression screenings
- Other screenings: HIV, hepatitis B and C, glaucoma, bone density, alcohol misuse, sexually transmitted infections, and abdominal aortic aneurysm
Part B also covers a one-time “Welcome to Medicare” preventive visit when you first enroll, plus a yearly wellness visit after that. These visits are designed to establish a baseline health profile and update your prevention plan each year.
Home Health Services
Both Part A and Part B can cover home health care, depending on the circumstances. Covered services include part-time or intermittent skilled nursing (wound care, injections, IV therapy, monitoring of serious illness), physical therapy, occupational therapy, speech-language pathology, and medical social services. If you’re already receiving skilled care, Medicare also covers a home health aide to help with bathing, grooming, walking, feeding, and changing bed linens.
Home health benefits also extend to durable medical equipment and medical supplies for use at home. You don’t need a prior hospital stay to qualify for home health under Part B, but you do need a doctor’s order confirming the care is medically necessary.
What Parts A and B Cost in 2025
Most people don’t pay a premium for Part A because they or a spouse earned enough work credits through payroll taxes. If you don’t qualify for premium-free Part A, you’ll pay up to $518 per month in 2025 (or $285 if you have at least 30 quarters of work history).
Part A has an inpatient hospital deductible of $1,676 per benefit period in 2025. For hospital stays, you pay nothing for the first 60 days after meeting that deductible. Days 61 through 90 cost $419 per day, and lifetime reserve days cost $838 per day. For skilled nursing facility stays, days 1 through 20 are fully covered after the deductible, days 21 through 100 cost $209.50 per day, and after day 100, you pay everything.
The standard Part B premium is $185 per month in 2025, with an annual deductible of $257. After meeting the deductible, you typically pay 20% of the Medicare-approved amount for most services, including durable medical equipment.
Late Enrollment Penalties
If you don’t sign up for Part B when you’re first eligible and don’t have qualifying coverage through an employer, you’ll face a permanent penalty. Your premium increases by 10% for every full year you could have enrolled but didn’t. This surcharge applies for as long as you have Part B, which for most people means the rest of their life. Signing up on time, or understanding whether your current coverage qualifies as a valid delay, can save you significant money over the years.
What Parts A and B Don’t Cover
Original Medicare has some well-known gaps. Parts A and B do not cover:
- Dental care: routine cleanings, fillings, extractions, and dentures
- Vision: eye exams for prescription glasses and the glasses themselves
- Hearing: hearing aids and the fitting exams for them
- Long-term care: custodial care in a nursing home when you don’t need skilled medical services
- Cosmetic surgery
- Routine physical exams: these are distinct from the covered annual wellness visit, which focuses on prevention planning rather than a head-to-toe physical
These exclusions are a major reason many people add supplemental coverage. Medicare Advantage plans (Part C) often bundle dental, vision, and hearing benefits. Medigap policies help cover out-of-pocket costs like deductibles and coinsurance. And Part D adds prescription drug coverage, which Original Medicare largely lacks outside of hospital-administered medications and certain preventive vaccines covered under Part B.