Medicare's 100-Day Rule for Skilled Nursing Facility Coverage in Wisconsin

If a family member in Wisconsin is heading from the hospital to a skilled nursing facility, you've probably heard the phrase "Medicare covers 100 days." That's true, sort of. The actual rule is narrower than most Wisconsin families realize, and the difference between a fully covered stay and a surprise bill comes down to a handful of conditions that the hospital discharge planner may or may not explain in detail.

This is the rule that catches families off guard more than almost any other piece of Medicare. Here's exactly how skilled nursing facility coverage works in Wisconsin under Medicare Part A, what the 3-day hospital rule means, what WI residents will pay each day, and when coverage stops.

What Medicare Considers a Skilled Nursing Facility

A skilled nursing facility, or SNF, is a Medicare-certified facility that provides short-term recovery care after a hospital stay. Think rehab after a hip replacement at a Wisconsin hospital, IV antibiotics for a serious infection, or wound care that needs a nurse. SNFs are not the same as long-term nursing homes, even though many Wisconsin facilities offer both kinds of care under one roof.

This distinction matters because Medicare does not pay for custodial care. If your loved one needs help with bathing, dressing, or eating but doesn't need a skilled professional like a registered nurse or licensed therapist, Medicare won't cover the stay no matter how necessary it feels. Custodial care falls under Wisconsin's Medicaid program or private pay.

The 3-Day Hospital Rule

Before Medicare will cover a single day in an SNF, you have to clear the 3-day hospital rule. This is where most denied claims in Wisconsin start.

To qualify, the patient needs to be formally admitted to a Wisconsin hospital as an inpatient for at least 3 consecutive days, not counting the day of discharge. Time spent in the emergency room or under observation status does not count, even if you slept in a hospital bed and ate hospital meals. This trips up a huge number of Wisconsin families because observation can look identical to inpatient care from the patient's perspective.

If your loved one is admitted on a Monday and discharged Thursday, you have your three midnights. If they came in through the ER Friday night, stayed under observation until Sunday, and were admitted as inpatient Sunday afternoon, you only have Sunday and Monday as inpatient days. SNF coverage gets denied.

Always ask the Wisconsin hospital directly whether the patient is inpatient or under observation. Federal law requires hospitals to give you a MOON notice (Medicare Outpatient Observation Notice) within 36 hours if you've been under observation for more than 24 hours, but the notice doesn't always reach families in time to act.

The Three Other Coverage Conditions

Past the 3-day rule, four more conditions apply for WI residents:

• The SNF must be Medicare-certified. Most facilities in Wisconsin are, but not all. Confirm before admission.
• You must enter the SNF within 30 days of leaving the hospital. Wait longer and you start over.
• You need daily skilled care. That means physical therapy, occupational therapy, speech therapy, IV medications, wound care, or skilled nursing observation — at least 5 days a week for therapy or 7 days a week for nursing.
• The care must relate to the condition treated in the hospital or one that developed during the stay. You can't go in for pneumonia and then get covered SNF care for an old back injury.

How the 100 Days Actually Break Down

Once you qualify, here's what Medicare pays per benefit period in Wisconsin:

• Days 1 through 20: Medicare pays 100%. You owe nothing.
• Days 21 through 100: Medicare pays the bulk of the cost, but you owe a daily coinsurance of $209.50 in 2026 ($204 in 2025).
• Day 101 and beyond: Medicare pays nothing. You're on your own.

That coinsurance adds up fast. Eighty days at $209.50 is $16,760. This is one of the gaps that Medicare Supplement plans are specifically designed to cover. Most Medigap plans available to Wisconsin residents cover the full SNF coinsurance, which is a big reason families in WI add a supplement before they need one. If you're weighing options, Plan G versus Plan N both include the SNF coinsurance benefit.

What "Benefit Period" Actually Means

Medicare doesn't count SNF coverage by calendar year. It counts by benefit period, and this is one of the most counterintuitive parts of what Medicare covers.

A benefit period starts the day you're admitted as an inpatient and ends 60 consecutive days after you've stopped receiving inpatient hospital or skilled nursing care. Once those 60 days are up, the next hospital admission opens a new benefit period — and you get a fresh 100 days of SNF coverage.

In theory, a Wisconsin Medicare beneficiary could use multiple 100-day SNF benefits in a single year if hospital admissions are spaced out enough. In practice, what usually happens is that someone uses part of one benefit period, returns home for fewer than 60 days, and then needs more care. In that case, the same benefit period continues and the day count picks up where it left off.

When Medicare Stops Paying Before Day 100

This is the part that catches Wisconsin families completely off guard. Medicare doesn't guarantee 100 days. It guarantees up to 100 days, as long as you keep needing skilled care and keep making progress.

If the SNF's interdisciplinary team decides the patient has plateaued — meaning no longer improving from therapy — Medicare can stop paying even if only 30 or 40 days have been used. The facility will issue a Notice of Medicare Non-Coverage (NOMNC) at least 2 days before discharge or before billing changes over.

You have the right to appeal a Medicare coverage decision the same day you receive the NOMNC. The appeal goes to a Beneficiary and Family Centered Care Quality Improvement Organization (BFCC-QIO), and they typically make a decision within 72 hours. While the appeal is pending, Medicare keeps paying. It's worth filing if you genuinely believe more skilled care is needed.

What Medicare Advantage Does Differently in Wisconsin

If you have a Medicare Advantage plan in Wisconsin, the 100-day SNF benefit still exists, but the rules can vary by plan. Many Wisconsin Medicare Advantage plans have eliminated the 3-day hospital requirement entirely, which is genuinely helpful. Others require prior authorization before you can transfer to an SNF, which can mean delays at exactly the wrong moment.

The cost structure also differs. Instead of $0 for the first 20 days and $209.50 after, Medicare Advantage plans typically charge a flat daily copay starting on day 1. Some are cheaper than Original Medicare's coinsurance after day 20; others are more expensive overall. The type of Medicare Advantage plan you have — HMO or PPO — also affects which Wisconsin SNFs you can use. Check your Evidence of Coverage or call your plan before assuming you know what you'll owe. If you're considering switching back, here's how to move from Medicare Advantage to Medigap.

What Isn't Covered Even Under the 100 Days

Even during a fully covered stay at a Wisconsin SNF, certain items aren't included:

• Private rooms, unless medically necessary
• Personal items like a phone or TV
• Custodial care services if that becomes your only need
• Long-term care, period. Medicare is not a long-term care program

This last point is the biggest source of confusion in all of Medicare. If your family member needs ongoing nursing home care because they cannot live independently anymore, Medicare won't pay for it. The options for Wisconsin residents are private pay, long-term care insurance, or qualifying for Medicaid through dual eligibility by spending down assets.

What to Do Before You Need It

The SNF benefit is one of those things you don't think about until a family member is being discharged from a Wisconsin hospital. By then, the questions come fast and the answers are buried in policy language. A few things WI residents can do ahead of time:

• Confirm whether your current coverage is Original Medicare or Medicare Advantage, and look up your SNF cost-sharing in either case
• If you have Original Medicare, look at whether a Medigap policy makes sense to cover the day 21-100 coinsurance
• Keep a list of Medicare-certified SNFs in your area, including any with strong star ratings on Medicare.gov — see how Medicare star ratings work
• If a hospital stay starts, ask immediately and in writing whether the admission is inpatient or observation
• Review the Medicare penalties to avoid so a coverage gap doesn't compound the problem

The 100-day rule is generous when it works. The problem is the conditions that have to line up for it to work, and the fact that most Wisconsin families learn about them after the fact. Knowing how the rule operates before you need it puts you in a much better position to push back when something gets denied. A licensed Medicare agent in Wisconsin can walk through your specific coverage and flag the gaps that matter most for your situation.