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

Medicare Part A pays for inpatient hospital care — when you stay overnight in a hospital bed. It also covers skilled nursing facilities (a step-down facility after hospitalization), hospice care, and some home health services. You do not pay a monthly premium for Part A if you or your spouse paid Medicare taxes for at least 10 years while working.

Medicare Part B pays for outpatient services: doctor office visits, lab tests, imaging (X-rays, ultrasounds), physical therapy, and preventive screenings. Part B has a monthly premium, which changes each year. Most people pay this premium automatically through Social Security or a bank account.

The clearest way to remember the difference: Part A is for staying in the hospital; Part B is for everything else your doctor does.

Key Takeaways

  • Part A covers overnight hospital stays and skilled nursing care after hospitalization; Part B covers doctor visits, tests, and outpatient procedures.
  • Most people do not pay a monthly premium for Part A if they worked and paid Medicare taxes for 10 years, but Part B always has a monthly premium.
  • Both parts have deductibles and copays, and the amounts change each year.
  • You can turn down Part B when you first become may be able to access, but if you enroll late without a may have access to reason, you may pay a permanent penalty.
  • Part A and Part B together do not cover everything — dental, vision, hearing aids, and long-term custodial care are not included.

What Part A actually pays for

Part A covers the full cost of your hospital room, meals, and basic nursing care for the first 60 days of a hospital stay in a benefit period. After 60 days, you pay a daily copay. After 90 days, the copay increases. A benefit period starts when you enter the hospital and ends after you have been out for 60 consecutive days.

Part A also pays for up to 100 days in a skilled nursing facility — but only if you were hospitalized for at least three days first, and only if you need skilled care (like wound care or physical therapy), not just help with daily activities. The first 20 days are fully covered; days 21 through 100 require a daily copay.

Hospice care and some home health services are covered under Part A as well. Home health is free if a doctor orders it and you meet the criteria (homebound, need skilled care). Hospice is covered when a doctor certifies you have six months or less to live.

What Part B actually pays for

Part B covers doctor office visits, whether your primary care doctor or a specialist. It pays 80 percent of the approved amount after you meet your annual deductible; you pay the remaining 20 percent. The deductible resets every January.

Preventive services covered under Part B include annual wellness visits, cancer screenings (mammogram, colonoscopy, Pap smear), bone density scans, cardiovascular screenings, and diabetes screenings. Most preventive services have no copay if you see an in-network provider.

Part B also covers lab work, imaging, outpatient surgery, mental health counseling, physical therapy, occupational therapy, and durable medical equipment like wheelchairs, walkers, and oxygen. Ambulance services are covered if medically necessary.

How much you pay out of pocket

Part A has an annual deductible that applies per benefit period — meaning if you are hospitalized twice in the same year, you may pay the deductible twice. The deductible covers your first 60 days of hospital care. After that, you pay a daily copay for days 61 through 90, and a higher daily copay for days 91 through 150 (your "lifetime reserve days").

Part B has a separate annual deductible. Once you meet it, Medicare pays 80 percent of approved charges and you pay 20 percent. The deductible and the 20 percent coinsurance are separate costs — meeting the Part B deductible does not reduce what you owe for Part A, and vice versa.

Both deductibles and copays change every January. The Centers for Medicare & Medicaid Services (CMS) announces the new amounts in the fall, and they are published on Medicare.gov.

When you must enroll and what happens if you do not

You become may be able to access for Medicare at age 65. Your initial enrollment period is the three months before the month you turn 65, the month you turn 65, and the three months after — seven months total.

Part A enrollment is automatic if you are already receiving Social Security benefits. If you are not yet taking Social Security, you must enroll in Part A during your initial enrollment period or you may face a permanent penalty.

Part B enrollment is not automatic. If you do not enroll during your initial enrollment period and you do not have other may have access to coverage (like employer health insurance), you will pay a permanent 10 percent increase to your Part B premium for each full year you delayed. This penalty stays with you for life, even after you do enroll.

If you have employer coverage through your job or your spouse's job, you may be able to delay Part B without penalty. You will need to show proof of that coverage when you eventually enroll.

What Part A and Part B do not cover

Neither part covers dental care, vision care, or hearing aids. Routine eye exams, glasses, dentures, and hearing aids are your responsibility unless you purchase a separate plan that includes them.

Long-term custodial care — help with bathing, dressing, and toileting in your home or in a nursing home — is not covered by Part A or Part B. Medicaid may cover this if you meet income and asset limits, but Medicare does not.

Prescription drugs are not covered by Part A or Part B. You need a separate plan called Part D to cover medications. Certain vaccines and some preventive medications are exceptions and may be covered under Part B.

Part A and Part B versus other Medicare options

Original Medicare consists of Part A and Part B. You can use any doctor or hospital that accepts Medicare, and you have flexibility in where you receive care.

Medicare Advantage (Part C) is an alternative to Original Medicare. It is offered by private insurance companies and combines Part A, Part B, and usually Part D into one plan. Most Advantage plans require you to use doctors and hospitals in their network, and many have lower out-of-pocket costs than Original Medicare — but you pay a monthly premium in addition to your Part B premium.

If you choose Original Medicare (Part A and Part B), you can purchase a Medigap policy to help cover the deductibles, copays, and coinsurance that Original Medicare does not pay. Medigap policies are sold by private insurers and have their own monthly premiums.

Frequently Asked Questions

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

No. You can decline Part B if you have other health coverage, such as employer insurance. However, if you do not enroll when you are first may be able to access and you lose that other coverage later, you will owe a permanent penalty on your Part B premium. The penalty is 10 percent for each full year you delayed.

Can I switch from Part A and Part B to Medicare Advantage later?

Yes. You can switch during the Annual Enrollment Period (October 15 to December 7 each year) or during the Medicare Advantage Open Enrollment Period (January 1 to March 31). If you switch back to Original Medicare after being in an Advantage plan, you may want to enroll in Medigap during your open enrollment window to avoid higher premiums.

What is the difference between a copay and coinsurance?

A copay is a fixed dollar amount you pay for a specific service — for example, $25 for a doctor visit. Coinsurance is a percentage of the cost you pay after meeting your deductible — for example, 20 percent of the approved charge for an outpatient procedure. Part B typically uses coinsurance; Part A uses copays for hospital stays beyond 60 days.

If I have both Part A and Part B, am I fully covered?

No. Part A and Part B have deductibles, copays, and coinsurance you must pay. They also do not cover dental, vision, hearing aids, or prescription drugs. Many people purchase Medigap or enroll in Medicare Advantage to reduce out-of-pocket costs.

Does Part B cover my annual physical?

Part B covers one annual wellness visit with no copay if you see a provider who accepts Medicare assignment. This is different from a traditional physical exam. If your doctor performs additional services beyond the wellness visit, you may owe copays for those services.