Part A covers hospital care, Part B covers doctor visits and outpatient services

Medicare Part A pays for inpatient hospital stays, skilled nursing facility care after a hospital stay, hospice care, and some home health services. Medicare Part B pays for doctor office visits, preventive care, lab tests, imaging, outpatient surgery, and medical equipment like wheelchairs or oxygen. Most people get both parts together, but they work differently: Part A has a deductible per hospital stay, while Part B has a yearly deductible and then a 20 percent coinsurance on most services.

If you are already on Medicare or turning 65, you will encounter both parts during enrollment. Understanding what each one covers helps you know what costs you are responsible for and whether you need additional coverage like a Medigap plan or Medicare Advantage.

Key Takeaways

  • Part A covers hospital stays and skilled nursing care; Part B covers doctor visits, preventive care, and outpatient services.
  • Part A has a deductible per hospital stay; Part B has a yearly deductible and 20 percent coinsurance after that.
  • Most people are automatically enrolled in both parts at 65 if they are receiving Social Security, but you can decline Part B if you have other coverage.
  • If you miss the enrollment window for Part B, you may pay a permanent penalty on your premium, so timing matters.

What Medicare Part A Covers

Part A covers the cost of a hospital room, meals, nursing care, and necessary medical supplies during an inpatient stay—meaning you are admitted to the hospital and stay overnight. It also covers up to 100 days in a skilled nursing facility (a facility that provides medical care beyond what a regular nursing home offers) if you are admitted within 30 days of a hospital stay of at least three days. The facility must be Medicare-certified.

Part A also pays for hospice care if you have a terminal illness and choose comfort care instead of treatment, and it covers some home health services—like nursing visits or physical therapy at home—if you are homebound and your doctor orders the care. Home health services under Part A are free once you meet the Part A deductible; there is no additional coinsurance.

In 2024, the Part A deductible is $1,632 per hospital stay. After you pay that, Part A covers all hospital costs for days 1 through 60. Days 61 through 90 require a daily coinsurance amount (the hospital charges you a set amount per day). Beyond 90 days, you can use lifetime reserve days, but those also have a daily coinsurance. Once you go 60 days without a hospital stay, the deductible resets.

What Medicare Part B Covers

Part B covers doctor office visits, whether your doctor is in a hospital, clinic, or private practice. It pays for preventive services like annual wellness visits, cancer screenings, vaccinations, and cardiovascular screenings—usually with no cost to you if your doctor accepts Medicare assignment. It also covers lab tests, X-rays, ultrasounds, and other diagnostic imaging ordered by your doctor.

Part B pays for outpatient surgery (surgery where you go home the same day), emergency room visits, urgent care, and mental health services. It covers durable medical equipment like wheelchairs, walkers, oxygen equipment, and diabetic supplies. Physical therapy, occupational therapy, and speech therapy are covered under Part B when medically necessary and ordered by a doctor.

In 2024, the Part B yearly deductible is $240. After you meet that, Medicare pays 80 percent of the approved amount for most services, and you pay 20 percent coinsurance. Some preventive services have no coinsurance. Part B also has a monthly premium (the amount varies by income) that is usually deducted from your Social Security check.

How Part A and Part B Work Together

When you are admitted to a hospital, Part A covers your inpatient stay. If your doctor orders tests, imaging, or consultations while you are in the hospital, those are included in Part A's coverage—you do not pay Part B coinsurance for services rendered during an inpatient hospital stay. However, once you are discharged and receive outpatient follow-up care, Part B takes over and you pay the Part B coinsurance.

If you receive care in a hospital outpatient department (such as an emergency room visit where you are not admitted, or an outpatient procedure), Part B covers it, not Part A. This is an important distinction because outpatient hospital services sometimes have higher coinsurance than office-based services.

Enrollment Timing and Automatic Coverage

If you are receiving Social Security benefits before age 65, you are automatically enrolled in both Part A and Part B when you turn 65. If you are not yet receiving Social Security, you must sign up during your Initial Enrollment Period, which is the three months before the month you turn 65, the month you turn 65, and the three months after. You can sign up online at Medicare.gov, by phone at 1-800-MEDICARE, or in person at your local Social Security office.

You can decline Part B if you have other health coverage through an employer or union, but you must do this in writing during your Initial Enrollment Period. If you decline Part B and later want to enroll, you may face a permanent penalty on your premium—7 percent per year for each year you were not enrolled. The exception is if you have employer coverage; you can enroll in Part B without penalty within eight months of losing that coverage.

Costs You Are Responsible For

Under Part A, you pay the deductible per hospital stay, then coinsurance for days 61 through 90 and beyond. You pay nothing for covered home health services or hospice care (though you may pay a small copay for hospice drugs and respite care). Skilled nursing facility care requires coinsurance starting on day 21.

Under Part B, you pay the yearly deductible, then 20 percent coinsurance on most services. Some preventive services are fully covered with no coinsurance. You also pay the monthly Part B premium regardless of whether you use services that month. Neither Part A nor Part B has an out-of-pocket maximum, meaning your costs can be unlimited if you have a serious illness or injury. This is why many people buy Medigap coverage or choose Medicare Advantage as an alternative.

Part A and Part B Versus Medicare Advantage

Original Medicare (Part A and Part B together) is a fee-for-service plan: you can see any doctor or hospital that accepts Medicare, and Medicare pays its share of the bill. You are responsible for deductibles and coinsurance, and there is no out-of-pocket maximum.

Medicare Advantage (Part C) is an alternative to Original Medicare offered by private insurance companies. It includes Part A and Part B coverage, usually with lower out-of-pocket costs and an out-of-pocket maximum, but it often requires you to use doctors and hospitals in a network. You must have both Part A and Part B to enroll in Medicare Advantage. Some people choose Medicare Advantage for the lower costs; others prefer Original Medicare for the freedom to see any provider.

Frequently Asked Questions

Do I have to take Part B when I turn 65?

No. If you have health coverage through an employer or union, you can decline Part B without penalty. You must notify Medicare in writing during your Initial Enrollment Period. If you decline and later want to enroll, you may pay a permanent penalty unless you had employer coverage when you declined.

What happens if I miss my enrollment important date?

If you miss your Initial Enrollment Period and do not have a may have access to reason (such as employer coverage), you pay a permanent penalty on your Part B premium of 10 percent for each full year you were not enrolled. You can enroll during the General Enrollment Period (January 1 through March 31 each year), but the penalty applies.

Does Part B cover my doctor's office visit if I am in the hospital?

No. While you are an inpatient in the hospital, Part A covers all medically necessary services, including doctor visits, tests, and consultations. You do not pay Part B coinsurance for services provided during an inpatient stay. Part B applies to outpatient care after you are discharged.

What is the difference between a hospital stay and outpatient care?

An inpatient hospital stay means you are admitted to the hospital and stay overnight; Part A covers this. Outpatient care means you receive treatment and go home the same day (such as an emergency room visit where you are not admitted, or an outpatient surgery); Part B covers this.

Can I have both Original Medicare and Medicare Advantage at the same time?

No. You must choose one or the other. If you enroll in Medicare Advantage, you are still covered by Part A and Part B, but through the private insurance company's plan instead of Original Medicare. You can switch between them during the Annual Enrollment Period (October 15 through December 7 each year).