Medicare Part A is the hospital insurance piece of Original Medicare. It covers inpatient hospital stays, skilled nursing facility care after a qualifying hospital admission, hospice care for terminal illness, and limited home health services in certain circumstances. For the vast majority of Medicare beneficiaries — roughly 99% of people who enroll — Part A comes with no monthly premium because they paid Medicare payroll taxes for at least 10 years during their working lives. That’s where the popular idea that “Medicare is free” comes from. It’s only true for Part A, and only for people with sufficient work history.
Even without a premium, Part A has meaningful cost-sharing when you actually use it. The structure is unlike anything you’ve likely encountered in private insurance. Benefit periods, lifetime reserve days, and per-day coinsurance for extended stays are concepts specific to Medicare that consistently surprise people who haven’t studied them. If you’re planning on Original Medicare without a Medigap supplement, understanding exactly what Part A’s cost exposure looks like is not optional — it’s essential.
What Part A Actually Covers
Inpatient hospital care is the core Part A benefit. When you’re formally admitted as an inpatient to an acute care hospital, Part A covers a semi-private room (Medicare pays for the least expensive appropriate accommodation unless a private room is medically necessary), meals, general nursing services, drugs administered as part of your inpatient treatment, laboratory work, imaging, operating room and recovery room costs, and other medically necessary hospital services and supplies during the stay. Private-duty nursing, personal convenience items like private room upgrades beyond medical necessity, and phone or TV charges are not Part A benefits — those come out of your pocket regardless of your Medicare coverage.
Skilled nursing facility (SNF) care is covered under Part A after a qualifying inpatient hospital stay. The key requirements are that you had a qualifying inpatient stay of at least 3 consecutive days (not counting the day of discharge), you were admitted to the SNF within 30 days of that hospital discharge, and you need skilled nursing or skilled rehabilitative therapy services on a daily basis. If all three conditions are met, Part A covers up to 100 days in the SNF per benefit period. Days 1 through 20 are fully covered with no cost-sharing. Days 21 through 100 require a daily coinsurance of $209.50 per day in 2025.
Hospice care is covered under Part A for people who are certified by a physician as terminally ill with a life expectancy of 6 months or less if the illness runs its natural course, and who elect hospice care rather than curative treatment. Hospice is one of Medicare’s most comprehensive benefit structures: it covers nursing visits, physician services, medications for pain and symptom management, counseling, medical social services, short-term inpatient care for pain control or caregiver relief, and respite care. The cost-sharing in hospice is minimal — a small copay for outpatient drugs used for comfort care and a 5% coinsurance for inpatient respite stays. Hospice is significantly underused, partly because families are reluctant to accept the “6 months or less” framing, but the benefit is generous and the goal is quality of life, not giving up.
The Benefit Period: How It Works and Why It Matters
This is the feature of Part A that catches people off guard most often. Most private insurance uses a calendar year as the basis for cost-sharing: your deductible resets January 1 and accumulates through December 31. Medicare Part A doesn’t work that way. It uses benefit periods.
A benefit period begins the day you’re admitted as an inpatient to a hospital or skilled nursing facility. It ends when you’ve been out of inpatient care — both hospital and SNF — for 60 consecutive days. When a new benefit period begins, a new deductible begins with it. In 2025, the Part A deductible is $1,676 per benefit period. There is no limit on how many benefit periods you can have in a year, and there’s no limit on how many times you can pay the Part A deductible. If you’re hospitalized in February, discharged, completely recover for 61 days, then hospitalized again in the fall, you’ll pay two full deductibles in the same calendar year.
That’s not hypothetical. It happens frequently. People with chronic conditions that require repeated hospitalizations can face multiple deductibles in a year. This is one of the central arguments for either a comprehensive Medigap plan (which covers the Part A deductible) or Medicare Advantage (which replaces the benefit period structure with a different cost-sharing model that has an annual out-of-pocket maximum).
Hospital Cost-Sharing Day by Day
Within a single benefit period, the cost-sharing for inpatient hospital stays is structured by day. Days 1 through 60 are covered after the deductible with no additional daily cost to you. Days 61 through 90 cost $419 per day in 2025 — that’s your coinsurance on top of everything you’ve already paid. Beyond day 90, Medicare gives you access to 60 lifetime reserve days with a daily coinsurance of $838 per day in 2025. Lifetime reserve days are a one-time pool for your entire Medicare lifetime, not a per-year or per-benefit-period resource. You can use them strategically — you can elect not to use them for a given stay if you prefer to exhaust them later — but once they’re gone, they’re gone permanently.
After you exhaust your lifetime reserve days, Medicare Part A pays nothing for additional hospital days. You’re responsible for the full cost of the hospital stay, which at an acute care hospital in 2025 can easily exceed $3,000 to $5,000 per day depending on the facility and the level of care you need. For someone facing a very long hospitalization — serious illness, complicated surgery recovery, extended ICU care — the out-of-pocket exposure under Original Medicare without supplemental coverage is not just uncomfortable, it’s potentially financially catastrophic.
This is why brokers consistently emphasize either a Medigap Plan G (which covers the Part A coinsurance and lifetime reserve days completely after the Part A deductible) or Medicare Advantage (which caps total annual exposure at the plan’s out-of-pocket maximum). Neither is free, but both are almost certainly less expensive than paying day-by-day coinsurance for a long hospitalization.
Skilled Nursing Facility Coverage: The Details
The 3-day qualifying inpatient hospital stay requirement for SNF coverage is one of the most misunderstood rules in all of Medicare. And it catches people at the worst possible time — when they’re already dealing with a hospitalization and then need rehabilitation care. The rule requires that you were formally admitted as an inpatient (not held under observation status) for at least 3 consecutive days, and the day of discharge doesn’t count toward the 3 days. So if you’re admitted Monday and discharged Thursday, that’s 3 qualifying days (Monday, Tuesday, Wednesday) and you meet the requirement. Admitted Monday and discharged Wednesday — that’s only 2 days and you don’t qualify.
The daily coinsurance for SNF days 21 through 100 adds up fast. At $209.50 per day for up to 80 days, the maximum coinsurance exposure for a full 100-day SNF stay is $16,760. That’s a significant out-of-pocket cost on top of anything you paid during the hospital stay that triggered the SNF benefit. Most comprehensive Medigap plans cover the SNF daily coinsurance, which is one of the reasons the Medigap benefit has real value for older beneficiaries who statistically have higher odds of needing rehabilitation or skilled nursing care.
After 100 days in the SNF, Medicare pays nothing. You’re either paying privately (which at a skilled nursing facility can run $200 to $500 or more per day depending on location), qualifying for Medicaid (which requires meeting both medical and financial eligibility criteria), or relying on long-term care insurance if you have it. Medicare was never designed to be a long-term nursing home benefit. It covers skilled, rehabilitative care for a limited period. People who need months or years of custodial care — help with bathing, dressing, eating, mobility — generally aren’t covered by Medicare for that care unless there’s a concurrent skilled nursing need. Long-term care funding is a separate, significant planning challenge that Medicare doesn’t solve.
Observation Status: The Hidden Trap
Here’s a situation that frustrates Medicare beneficiaries more than almost any other. You go to the hospital. You’re in a hospital bed for 3 or 4 days. You assume you’ve been admitted. You get discharged to a skilled nursing facility for rehabilitation. And then you get a bill for the entire SNF stay because, it turns out, you were never formally admitted as an inpatient — you were held under observation status, which is technically an outpatient status even when you’re lying in a hospital bed for several days.
Observation status is billed under Part B rather than Part A. It doesn’t count toward the 3-day inpatient requirement for SNF coverage. And because you’re technically an outpatient, any drugs administered during an observation stay may be billed as outpatient drugs under Part B rather than being covered as part of an inpatient stay. The financial implications can be enormous. Hospitals increasingly use observation status due to complex Medicare payment rules and audit concerns, and the number of observation stays has grown significantly over the past decade. Congress has debated fixes, there has been litigation, and CMS has issued guidance, but as of 2025 the fundamental problem remains: observation days don’t count as inpatient days for SNF qualification purposes.
What can you do? When you or a family member is hospitalized, specifically ask the hospital whether you’ve been formally admitted as an inpatient or placed under observation status. If it’s observation, ask your doctor whether inpatient admission is clinically appropriate and advocate for a formal admission order if it is. If you’re near the 3-day mark, make sure the hospital is tracking your inpatient days correctly. It’s also worth knowing that Medicare requires hospitals to notify patients in observation status using a standardized notice called the MOON (Medicare Outpatient Observation Notice) within 36 hours of placing you under observation or before discharge if sooner. If you receive one of these notices, it’s your signal to ask questions immediately.
Home Health Coverage Under Part A
Medicare covers limited home health services under both Part A and Part B, and the distinction between which part covers a given episode of home health can be technical. Broadly, Part A covers home health when you’ve had a qualifying inpatient hospital or SNF stay and continue to need skilled care at home afterward. Part B covers home health as an outpatient benefit when there’s no qualifying stay. In practice, both pathways have the same coverage rules for what qualifies.
To be covered, you must be homebound — meaning it requires considerable and taxing effort to leave home. You need skilled nursing care or skilled therapy (physical, occupational, or speech therapy) on at least a part-time or intermittent basis. Your doctor must certify a plan of care and that care must be provided by a Medicare-certified home health agency. Covered services include skilled nursing visits, physical therapy, occupational therapy, speech therapy, home health aide services when you’re also receiving skilled care, and medical social services. These services are covered at 100% with no deductible and no coinsurance — they’re genuinely free under Medicare when you meet the qualifying criteria.
What’s not covered: 24-hour home care, homemaker services, personal care aide services (bathing, dressing) without a concurrent skilled nursing need, meals delivered to the home, and transportation. Custodial home care is the same story as custodial nursing home care — Medicare doesn’t cover it. People who need ongoing daily assistance at home must fund that through personal resources, Medicaid if eligible, long-term care insurance, or a combination of all three.
Part A Costs for People Without Enough Work History
If you haven’t accumulated 40 quarters of Medicare-covered employment, you can still buy into Part A. With 30 to 39 quarters, the Part A premium is $278 per month in 2025. With fewer than 30 quarters, it’s $505 per month. These premiums are in addition to the $185 monthly Part B premium that everyone pays. For someone who needs to purchase both at the higher rate, total Medicare Part A and Part B premiums can exceed $690 per month before any supplemental coverage is added.
Spouses can qualify for premium-free Part A based on their partner’s work record if the working spouse has at least 40 qualifying quarters. Divorced spouses who were married for at least 10 years may also qualify for premium-free Part A based on an ex-spouse’s work record, even if that ex-spouse is remarried. These spousal and ex-spousal eligibility pathways are important for people with limited or interrupted work histories — stay-at-home parents, people who worked primarily in cash economies, or people who immigrated later in life and haven’t accumulated enough quarters of their own.