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 visits, outpatient care, diagnostic tests, and medical equipment like wheelchairs or oxygen. Most people get both automatically at 65, and most pay no monthly premium for Part A because they or a spouse paid Medicare taxes while working.
The split exists because hospital care and doctor care work differently. A hospital admission is a major event with predictable costs; outpatient care is ongoing and variable. Part A uses a deductible system per hospital stay. Part B uses a deductible plus a percentage you pay (called coinsurance) after the deductible is met. Understanding which part covers what prevents surprises when you receive a bill.
Key Takeaways
- Part A covers inpatient hospital stays, skilled nursing care after hospitalization, and hospice; Part B covers doctor office visits, outpatient procedures, and preventive care.
- Most people pay no monthly premium for Part A if they worked and paid Medicare taxes for at least 10 years, but Part B has a monthly premium that increases if you delay enrollment.
- Part A has a deductible per hospital stay; Part B has an annual deductible and then you pay 20 percent coinsurance for most services.
- If you do not enroll in Part B when you first become may be able to access at 65, you may face a permanent penalty added to your monthly premium.
What Part A covers in detail
Part A pays for a hospital stay when you are admitted as an inpatient — meaning you stay overnight and occupy a hospital bed. It covers your room, meals, nursing care, and most tests and medications given during that stay. The coverage lasts up to 60 days per benefit period without additional cost beyond the deductible. If you stay longer, you pay a daily coinsurance amount for days 61 through 90, and a higher daily amount for days 91 through 150 (called "lifetime reserve days").
Part A also covers skilled nursing facility care — a facility that provides medical care and rehabilitation, not just custodial help — but only if you were hospitalized for at least three consecutive days first and are admitted within 30 days of leaving the hospital. The first 20 days are fully covered; days 21 through 100 require a daily coinsurance payment. Part A covers hospice care for people with a terminal diagnosis, and it covers some home health services when ordered by a doctor and provided by a Medicare-certified agency.
What Part B covers in detail
Part B covers doctor office visits, whether your doctor is in a hospital, clinic, or private practice. It pays for preventive care visits at no cost to you — annual wellness exams, cancer screenings, vaccinations, and other preventive services listed in your Medicare handbook. It also covers diagnostic tests ordered by a doctor: blood work, X-rays, ultrasounds, and imaging. Part B pays for outpatient surgery, emergency room visits, and urgent care.
Part B also covers medical equipment and supplies: wheelchairs, walkers, oxygen equipment, diabetic supplies, and similar items when prescribed by a doctor. It covers mental health services, physical therapy, and occupational therapy. Durable medical equipment — items meant to last and be reused — requires that you use a Medicare-approved supplier, or Part B will not pay. Part B does not cover routine dental, vision, or hearing care, though some preventive vision and hearing services may be covered in limited circumstances.
How the costs differ between Part A and Part B
Part A uses a benefit period system. A benefit period begins the day you enter a hospital and ends 60 days after you leave without being readmitted. If you are readmitted after those 60 days, a new benefit period starts. In 2024, the Part A deductible per benefit period is $1,632, though this amount changes each year. Once you pay that deductible, Part A covers your inpatient hospital care with no additional cost for the first 60 days.
Part B works differently. You pay a monthly premium (in 2024, the standard amount is $164.90 per month for most people, but it varies based on your income). You also pay an annual deductible ($240 in 2024). After you meet the deductible, you pay 20 percent of the Medicare-approved amount for most services — your coinsurance. If a doctor does not accept Medicare assignment, you may owe more. These amounts change yearly, so check your Medicare summary each January.
When you must enroll and what happens if you delay
You become may be able to access for Medicare the month you turn 65. Your initial enrollment period runs for seven months: three months before the month you turn 65, the month you turn 65, and three months after. If you enroll during this window, your coverage starts the first day of the month you turn 65 (or the first day of the following month if you enroll in the first three months of your birthday month).
If you do not enroll in Part B during your initial enrollment period and you do not have other may have access to coverage, you will pay a permanent penalty. The penalty is 10 percent of the standard Part B premium for each full 12-month period you were may be able to access but not enrolled. This penalty stays on your premium for as long as you have Part B. Part A has no penalty if you delay, but you should enroll anyway because coverage is retroactive to the month you became may be able to access if you enroll within six months of that month.
How Part A and Part B work together
When you are hospitalized, Part A pays first. Part B covers the doctor who treats you during that hospital stay. When you leave the hospital and see your doctor in the office, Part B pays. If you go to a skilled nursing facility after the hospital, Part A pays for the facility care, and Part B covers the doctor visits during your stay there.
Together, Part A and Part B cover most medically necessary care, but they do not cover everything. Neither covers long-term custodial care (help with bathing, dressing, eating), routine dental or vision care, or hearing aids. Many people add Medigap (supplemental insurance) to cover costs that Part A and Part B do not, or they choose Medicare Advantage (Part C), which is an alternative way to receive Part A and Part B benefits through a private insurance company.
Frequently Asked Questions
Do I have to take Part B when I turn 65?
No, but if you delay and do not have other may have access to coverage, you will pay a permanent 10 percent penalty on your Part B premium. If you are still working and covered by your employer's health plan, you may be able to delay Part B without penalty — ask your employer's benefits office whether you may have access to for this exception.
What happens if I am hospitalized and do not have Part A?
You will owe the full cost of your hospital stay. Part A is free for most people, so there is no reason not to enroll. If you did not enroll when you turned 65, you can enroll during the general enrollment period (January 1 through March 31 each year), though your coverage will not start until July 1.
Does Part B cover my doctor's office visit if I have not met my deductible?
No. You pay the full cost of the visit until you meet your annual deductible. After that, you pay 20 percent coinsurance. Preventive care visits are an exception — they are covered at no cost even before you meet your deductible.
Can I have both Part A and Part B?
Yes. Most people have both. Part A and Part B are designed to work together. If you choose Medicare Advantage (Part C) instead, you still have Part A and Part B coverage, but you receive it through a private insurance company rather than directly from Medicare.
What is the difference between Part B coinsurance and a copay?
Coinsurance is a percentage of the cost you pay after meeting your deductible — usually 20 percent. A copay is a fixed dollar amount. Medicare Part B uses coinsurance, not copays. Some Medicare Advantage plans use copays instead, which may be easier to predict.