Medicare covers most hospital costs, but not all of them, and the amount you pay depends on which part of Medicare you have and how long you stay.

If you have Original Medicare (Part A and Part B), the hospital itself is covered under Part A — but you pay a deductible upfront, and after 60 days in the hospital, you start paying a daily coinsurance amount. If you have a Medicare Advantage plan (Part C), your out-of-pocket costs work differently and depend entirely on your plan's rules. Either way, Medicare does not cover 100 percent of your hospital bill.

The gap between what Medicare pays and what you owe is real money. Knowing exactly what that gap looks like — and when it starts — helps you plan and avoid surprises when you are admitted.

Key Takeaways

  • Original Medicare Part A covers inpatient hospital stays but requires you to pay a deductible ($1,632 in 2024, though this amount changes yearly) before coverage begins.
  • After 60 days in the hospital during a single stay, you pay a daily coinsurance amount ($408 per day in 2024) for days 61 through 90, and a higher amount for days 91 and beyond.
  • Medicare Advantage plans have their own cost-sharing rules, often including copays per hospital day rather than deductibles, and these vary by plan and insurer.
  • Hospital bills include room, meals, nursing care, and basic supplies, but you may receive separate bills for doctors, specialists, and certain equipment that are not covered the same way.
  • Supplemental insurance (Medigap) can cover some or all of the costs Medicare does not pay, but you must purchase it separately and it is not available to everyone.

How Original Medicare Part A Covers Hospital Stays

Original Medicare Part A covers inpatient hospital care — meaning you are admitted and stay overnight. The coverage includes your room, meals, nursing care, medications given in the hospital, medical equipment, and lab tests done during your stay. Part A does not cover the doctor's fees separately; those are billed under Part B.

You pay a deductible before Part A coverage kicks in. In 2024, that deductible is $1,632 per benefit period. A benefit period starts the day you enter the hospital and ends 60 days after you leave — if you go back into the hospital more than 60 days later, a new benefit period begins and you pay the deductible again. If you are admitted multiple times within 60 days, you pay the deductible only once.

After you meet the deductible, Medicare pays the full cost of your hospital stay for days 1 through 60. Starting on day 61, you pay a daily coinsurance amount — $408 per day in 2024 — for days 61 through 90. If you stay longer than 90 days, you enter what Medicare calls "lifetime reserve days," and you pay $816 per day (in 2024) for up to 60 additional reserve days in your lifetime. Once you use your 60 lifetime reserve days, you pay all costs.

Medicare Advantage Plans and Hospital Coverage

If you have a Medicare Advantage plan (Part C), your hospital coverage works under your plan's rules, not under the Original Medicare structure. Most Advantage plans charge a copay per hospital day — often $250 to $500 — rather than a deductible. Some plans waive the copay after a certain number of days. Others use coinsurance (you pay a percentage of the cost) instead.

Your out-of-pocket maximum matters here. Medicare Advantage plans must have an out-of-pocket maximum — the most you can pay in a year for covered services. Once you hit that limit, the plan pays 100 percent of covered costs for the rest of the year. Original Medicare has no out-of-pocket maximum, which is why some people buy supplemental coverage.

The exact copay, coinsurance, and out-of-pocket maximum for your Advantage plan are in your plan documents or on your insurer's website. If you are considering switching plans or are new to Medicare, comparing these numbers across plans in your area is important because they vary widely.

What Medicare Does Not Cover in the Hospital

Medicare Part A covers the hospital facility and its services, but certain costs are billed separately and fall under different rules. Doctor and specialist fees are billed under Part B, which has its own deductible ($240 in 2024) and coinsurance (usually 20 percent after you meet the deductible). If a cardiologist, surgeon, or radiologist sees you in the hospital, their bill comes separately from the hospital bill.

Some equipment and services are not covered at all. Private duty nursing (a nurse hired just for you, beyond what the hospital provides) is not covered. Certain medications not on Medicare's formulary, experimental treatments, and comfort items like a television or phone are your responsibility. If you want a private room instead of a semi-private one, you typically pay the difference.

Ambulance transport to the hospital is covered under Part B with 20 percent coinsurance, but only if it is medically necessary. Non-emergency transport is not covered.

Supplemental Insurance and What It Covers

Medigap (supplemental insurance) is sold by private insurers and designed to cover costs that Original Medicare leaves unpaid. Depending on which Medigap plan you buy, it can cover your Part A deductible, your daily coinsurance for days 61 through 90, and even your lifetime reserve day costs. Some Medigap plans also cover the Part B deductible and coinsurance.

Medigap is separate from Medicare and costs extra — premiums vary by plan type, your age, and your location. You can buy Medigap only if you have Original Medicare (Part A and Part B), not if you have a Medicare Advantage plan. There is a limited window to buy Medigap without medical underwriting: the six months after you turn 65 and enroll in Part B. Outside that window, insurers can deny you or charge more based on your health history.

If you already have a Medigap plan and are hospitalized, contact your Medigap insurer to ask what they will pay directly to the hospital or to you. Some plans pay the hospital; others reimburse you after you pay.

Understanding Your Hospital Bill After Discharge

Hospital bills are often confusing because they come in pieces. You may receive a bill from the hospital facility, a separate bill from the doctor who admitted you, bills from any specialists who saw you, and bills from the lab or imaging center if they are independent contractors. Each bill may have different coverage rules and cost-sharing amounts.

Review your bill carefully. Hospital billing errors are common — duplicate charges, charges for services you did not receive, and coding mistakes happen. If you see something you do not recognize, ask the hospital's billing department for an itemized explanation. Medicare also publishes what it paid the hospital, which you can compare to your bill.

If you have Original Medicare and a Medigap plan, send copies of your hospital bills and Medicare's explanation of benefits to your Medigap insurer so they know what to pay. If you have a Medicare Advantage plan, contact your plan to confirm what they will cover before you pay anything out of pocket.

Planning Ahead for Hospital Costs

Knowing your costs before admission is not always possible, but you can take steps now. If you have Original Medicare, consider whether Medigap makes sense for you — it costs money upfront but can save you thousands if you have a long hospital stay. If you have a Medicare Advantage plan, know your plan's copay structure and out-of-pocket maximum so you are not shocked by a bill.

Keep copies of your Medicare card, your plan documents, and any Medigap or Advantage plan information with you or give it to a family member. When you are admitted to the hospital, tell the admissions staff about all your coverage so they can bill correctly. Ask the hospital's financial counselor about payment plans if you cannot pay your share upfront — many hospitals offer them.

If you are facing a large hospital bill you cannot pay, contact your state's Patient Advocate Foundation or your local Area Agency on Aging; both can point you toward financial information programs and billing dispute resources.

Frequently Asked Questions

What happens if I stay in the hospital longer than 90 days?

After 90 days, you enter your lifetime reserve days. Medicare covers up to 60 additional reserve days in your lifetime, but you pay $816 per day (in 2024). Once you use all 60 reserve days, Medicare stops paying and you pay all costs. Reserve days do not renew each year — they are a one-time pool for your entire life.

Do I have to pay the Part A deductible every time I go to the hospital?

No. You pay it once per benefit period. A benefit period lasts from the day you enter the hospital until 60 days after you leave. If you are readmitted within those 60 days, you do not pay the deductible again. If you are readmitted more than 60 days later, a new benefit period starts and you pay the deductible again.

If I have a Medicare Advantage plan, do I still pay the Part A deductible?

No. Medicare Advantage plans replace Original Medicare, so you do not pay the Part A deductible. Instead, you pay whatever copay or coinsurance your plan specifies for hospital stays. Check your plan documents or call your plan to find out your exact cost.

Are doctor bills during a hospital stay covered under Part A or Part B?

Doctor bills are covered under Part B, not Part A. You pay the Part B deductible ($240 in 2024) and then 20 percent coinsurance for the doctor's services. This is separate from what you pay for the hospital facility itself under Part A.

Can I use my Medigap plan if I have a Medicare Advantage plan?

No. Medigap is only for people with Original Medicare. If you have a Medicare Advantage plan, you cannot buy Medigap. Your Advantage plan is your supplemental coverage.