Why Medicare Stops Paying for Skilled Nursing After 20 Days

Linda’s mother fell in her kitchen on a Tuesday in February and broke her hip. Surgery happened Wednesday morning, the orthopedist cleared her for rehab on Friday, and the hospital discharged her to a skilled nursing facility on Saturday. The admissions packet at the SNF mentioned Medicare coverage in passing. Linda assumed her mother had 100 days. On day 21, the SNF business office handed Linda a bill for $209.50 and explained that the daily coinsurance had kicked in. By day 30, Linda owed nearly $2,100 out of pocket. By day 60, that number was $8,200. Her mother needed another six weeks.

The 100-day myth

Medicare Part A covers SNF stays inside a defined benefit period, but the cost-sharing is back-loaded in a way most families do not see coming. Days 1 through 20 are covered in full, with no copay and no deductible. Days 21 through 100 carry a daily coinsurance, set at $209.50 in 2025 and adjusted by CMS each year. Day 101 onward, Medicare pays nothing. The full daily cost of the SNF, which runs $300 to $700 per day depending on the region, falls back on the beneficiary or family.

The 100 days is not a year-long benefit. It is tied to a benefit period that starts on the day the patient is admitted to a hospital or SNF and ends after they have been out of inpatient care for 60 consecutive days. A new benefit period restarts the counter, but it also restarts the Part A deductible.

The 3-day inpatient rule

Before Medicare pays for any SNF stay, the patient must have a qualifying inpatient hospital admission of at least three consecutive days, not counting the day of discharge. Observation status does not count, even when the patient stayed in a hospital bed overnight. This is the trap that catches a high share of families: a parent gets admitted under observation for two days, transferred to a third day still under observation, then discharged to rehab. The SNF stay is not covered, because the hospital stay never converted to inpatient.

The Center for Medicare Advocacy reports that observation-status complaints make up one of the largest categories of Medicare appeals. The fix is simple in theory: confirm inpatient admission status with the hospital case manager before discharge. Get it in writing.

What “skilled” means in practice

Medicare only pays the SNF benefit for care that requires daily skilled nursing or skilled therapy. The patient must need physical therapy, occupational therapy, speech therapy, or nursing-level care like wound dressings, IV medications, or respiratory therapy on a daily basis. The moment the care plan steps down to custodial care, which is help with bathing, dressing, eating, or moving without skilled rehab work, Medicare stops paying.

This rule cuts the 100 days short for many beneficiaries. A patient recovering from a hip replacement who plateaus in physical therapy at week four no longer qualifies. The SNF is required to issue a Notice of Medicare Non-Coverage, and the family has 48 hours to either appeal or pay privately.

The Medigap bridge

Days 21 through 100 are exactly the gap that a Medicare Supplement plan is built to absorb. Medigap Plan G, the most popular supplement plan for new Medicare enrollees, pays the daily SNF coinsurance in full. Plan N also pays it. A beneficiary on Original Medicare with a Plan G runs zero out-of-pocket cost during the entire 100-day SNF window, except for the Part A deductible at admission.

This is one of the strongest reasons to enroll in Medigap during the initial enrollment period, when no medical underwriting applies. Wait until later and the carrier can decline or rate up based on health history. For more on this trade-off, see Medicare Advantage versus Medigap explained.

Medicare Advantage plans handle SNF coverage differently. Most cap the daily copay at a lower number, $0 to $50 per day for the first 20 days, then $150 to $200 per day for days 21 onward, with their own network and prior-authorization rules. Total out-of-pocket exposure caps at the plan’s annual maximum, which runs $4,000 to $8,500 in 2025.

What to do at hospital discharge

Three actions before the patient leaves the hospital change the SNF financial picture entirely. First, confirm inpatient admission status, not observation, for at least three consecutive days. Second, request a copy of the hospital’s discharge summary and the SNF admission packet, then read the section on coverage limits. Third, if the patient is on Original Medicare without a Medigap plan, calculate the day-21 exposure and arrange the source of those funds before the bill arrives. For families weighing long-term planning, our guide to what Medicare covers walks through Parts A, B, C, and D in plain language.

FAQ Section

Does Medicare Advantage have the same 20-day rule? No. Medicare Advantage plans set their own SNF cost-sharing structure, with daily copays starting earlier or later depending on the plan. Most Advantage plans charge $0 for the first few days, then $150 to $200 per day from day 21 onward, capped at the plan’s out-of-pocket maximum.

What counts as the qualifying 3-day hospital stay? Three consecutive midnights as a formally admitted inpatient. Observation status, ER visits, and same-day surgery do not count, even if the patient was in a hospital bed. Confirm inpatient status with the hospital case manager in writing.

Can I appeal when the SNF says Medicare is no longer paying? Yes. The SNF is required to issue a Notice of Medicare Non-Coverage at least two days before stopping coverage. The patient can request an immediate review by the Quality Improvement Organization, which decides within 24 hours. Coverage continues during the review.

What happens after day 100? Medicare pays nothing after day 100 in a benefit period. The patient pays the full daily room and board, which runs $300 to $700 per day. A new 100-day benefit becomes available only after the patient has been out of inpatient care for 60 consecutive days.

Does Medigap cover the SNF coinsurance? Plan G and Plan N pay the SNF coinsurance for days 21 through 100 in full. Plan F, available only to beneficiaries who became eligible for Medicare before 2020, also covers it. Lower-letter plans like Plan A and Plan B do not.

Closing

The 100-day Medicare SNF benefit reads like a long runway. The structure underneath is a 20-day full-coverage window, an 80-day partial-coverage window with a daily coinsurance that compounds fast, and a hard wall on day 101. Families who plan for the gap have options. Families who learn about it from the SNF business office have a check to write.

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