Overview: Part A is often called "hospital insurance," but it covers several distinct categories of care — each with its own cost-sharing structure that exam questions frequently test.

What Part A Covers

Part A covers four primary categories:

Inpatient hospital care: Semi-private rooms, meals, general nursing, medications administered during the stay, and most hospital services following formal inpatient admission to an acute care, rehabilitation, or psychiatric hospital. (Note: inpatient psychiatric care has a 190-day lifetime limit.)
Skilled nursing facility (SNF) care: Short-term rehabilitative care after a qualifying hospital stay. To qualify, the patient must have had an inpatient hospital stay of at least three consecutive days (not counting the discharge day). Coverage includes semi-private room, meals, skilled nursing care, and physical, occupational, or speech therapy.
Hospice care: For beneficiaries with a terminal prognosis of six months or less who choose comfort-focused rather than curative care. Covered services include nursing visits, pain medications, durable medical equipment, aide services, and short-term inpatient respite care (up to five consecutive days at a time to give family caregivers a break).
Home health care: Part-time or intermittent skilled nursing or therapy for homebound patients who need professional services, with no cost-sharing for the services themselves (though durable medical equipment carries 20% coinsurance).

The Benefit Period Concept

Part A cost-sharing is organized around benefit periods, not calendar years. A benefit period begins on the day you are admitted as an inpatient to a hospital or SNF, and ends when you have gone 60 consecutive days without receiving any inpatient hospital or SNF care. There is no cap on how many benefit periods you can have — if you recover, spend 60 days without inpatient care, and then are admitted again, a new benefit period starts and the deductible resets.

Part A Cost-Sharing (2026)

Hospital Stay Duration	Beneficiary Pays
Deductible (per benefit period)	$1,736
Days 1–60	$0 coinsurance
Days 61–90	$434/day
Days 91–150 (lifetime reserve days)	$868/day
Beyond day 150 (reserve days exhausted)	100% of costs

SNF Stay Duration	Beneficiary Pays
Days 1–20	$0
Days 21–100	$217/day
Beyond day 100	100% of costs

Lifetime reserve days are a pool of 60 additional days that a beneficiary can draw on once their 90-day base runs out within a benefit period. Once used, they do not replenish — ever. This is one reason a catastrophic illness can be financially devastating under Original Medicare without supplemental coverage.

FAQ

Does Part A cover the doctor's services during a hospital stay?
No. This catches many exam-takers off guard. When you are admitted as an inpatient, the hospital's facility charges (room, nursing, meals, supplies) are billed under Part A. The physician's professional services — the surgeon, anesthesiologist, attending physician — are billed separately under Part B. A single hospitalization almost always triggers both Part A and Part B costs simultaneously.

What is the 3-day hospital rule for SNF coverage?
Before Medicare Part A will pay for SNF care, the patient must have been formally admitted (not held for "observation") as an inpatient for at least three consecutive calendar days, not counting the day of discharge. Observation status does not satisfy this requirement, which is a common point of confusion for patients and families.