The Four Parts of Medicare and What Each One Pays For
Medicare has four separate parts, and each one covers different things. Part A covers hospital stays, skilled nursing care after a hospital stay, hospice, and some home health services. Part B covers doctor visits, outpatient care, lab tests, imaging, and some preventive services. Part D covers prescription drugs. Part C, also called Medicare Advantage, is an alternative to Parts A and B offered by private insurance companies — it covers everything A and B do, but often with different costs and networks.
Most people who turn 65 are automatically enrolled in Parts A and B. Part D is separate and you choose it during your enrollment period. Part C replaces Parts A and B if you choose it instead. Understanding which part covers what matters because Medicare does not cover everything, and what you pay out of pocket depends on which parts you have.
Key Takeaways
- Part A covers hospital stays and skilled nursing facilities; Part B covers doctor visits and outpatient services; Part D covers prescription drugs; Part C is a private alternative that combines A and B coverage.
- Medicare does not cover dental, vision, hearing aids, or long-term custodial care in nursing homes, and these gaps are common reasons seniors buy supplemental insurance.
- You pay different amounts depending on your income and which parts you have — Part B and D premiums increase if your income was high two years ago.
- Preventive services like annual wellness visits, cancer screenings, and vaccines are covered at no cost when you see an in-network provider.
- Original Medicare (Parts A and B) has no network requirement, but Part C (Medicare Advantage) usually does, and out-of-network care costs more or is not covered.
What Part A Covers: Hospital and Skilled Nursing Care
Part A pays for inpatient hospital stays after you meet your deductible. In 2024, the deductible is $1,632 per benefit period — a benefit period starts when you enter the hospital and ends 60 days after you leave. If you go back to the hospital within 60 days, you are still in the same benefit period and do not pay another deductible. After you meet the deductible, Medicare covers all hospital costs for the first 60 days, then charges you a daily amount for days 61 through 90.
Part A also covers up to 100 days in a skilled nursing facility if you were hospitalized for at least three days first. Medicare covers all costs for the first 20 days, then charges you a daily amount for days 21 through 100. A skilled nursing facility is not the same as a regular nursing home — it provides medical care and rehabilitation, not just daily information. If you need help with bathing or dressing but not medical care, Part A does not cover it.
Part A covers hospice care for people with a terminal illness, and it covers some home health services — specifically, skilled nursing visits and physical therapy at home when ordered by your doctor. It does not cover ongoing personal care or housekeeping unless it is part of a skilled nursing visit.
What Part B Covers: Doctor Visits and Outpatient Services
Part B covers doctor visits, whether in an office or hospital outpatient department. It covers lab tests, X-rays, CT scans, and other diagnostic imaging. It covers physical therapy, occupational therapy, and speech therapy when ordered by your doctor. It covers mental health visits — both therapy and psychiatry — at the same rate as other doctor visits.
Part B also covers preventive services at no cost to you when you see an in-network provider. These include an annual wellness visit, colorectal cancer screening, mammograms, prostate cancer screening, bone density scans, diabetes screening, cardiovascular screening, and vaccines including flu, pneumonia, and shingles. You pay nothing for these services — no copay, no coinsurance — as long as your doctor accepts Medicare.
Part B has a yearly deductible ($240 in 2024) and then you pay 20% of the cost for most services. Your doctor's office bills Medicare first, and Medicare pays its share, then sends you a bill for your 20%. Some doctors charge more than Medicare allows, and if they do not accept Medicare, you may owe the full difference.
What Part D Covers: Prescription Drugs
Part D is prescription drug coverage run by private insurance companies under contract with Medicare. Each plan has a different list of covered drugs, called a formulary, and the drugs are organized into tiers with different costs. A generic drug might be tier 1 with a $5 copay, while a brand-name drug might be tier 3 with a $50 copay.
You choose a Part D plan during your initial enrollment period when you turn 65, or during the annual open enrollment period from October 15 to December 7. If you do not choose a plan when you are first may be able to access, you pay a penalty for each month you go without coverage — the penalty is added to your premium permanently. The penalty is roughly 1% of the national average Part D premium per month you were without coverage.
Part D coverage has a structure: you pay a monthly premium, then a deductible (up to $545 in 2024), then you pay your copay or coinsurance until you reach a certain spending level. After that, you enter the "donut hole" where you pay more out of pocket, and eventually catastrophic coverage kicks in where Medicare pays most of the cost. The exact amounts change each year.
What Medicare Does Not Cover
Medicare does not cover dental care, including cleanings, fillings, and extractions. It does not cover vision care or eyeglasses, though it covers one eye exam every two years if you have diabetes. It does not cover hearing aids or hearing exams, though it does cover some hearing tests as part of preventive care. These three gaps — dental, vision, and hearing — are the most common reasons seniors buy supplemental insurance.
Medicare does not cover long-term custodial care in a nursing home. If you need help with bathing, dressing, eating, or toileting but not medical care, that is custodial care and Medicare does not pay for it, even if you are in a nursing home. Part A covers skilled nursing care for up to 100 days after a hospital stay, but once that ends, you pay out of pocket or Medicaid covers it if you may have access to.
Medicare does not cover cosmetic surgery, weight loss surgery (except in specific cases), or most fertility treatments. It does not cover routine foot care, though it covers foot care for people with diabetes. It does not cover most over-the-counter medications or supplements. It does not cover private duty nursing or personal care attendants.
How Much You Pay: Premiums, Deductibles, and Coinsurance
Part A has no monthly premium for most people because they paid into Medicare through payroll taxes while working. Part B has a monthly premium that increases each year — in 2024 it is $164.90 for most people, but it is higher if your income was above a certain level two years ago. The income thresholds are adjusted each year, and higher-income seniors pay an additional amount called Income-Related Monthly Adjustment Amount (IRMAA).
Part D premiums vary by plan and change each year. Part C premiums also vary — some plans have no premium, while others charge $50 to $200 or more per month. Part C plans often have lower deductibles and copays than Original Medicare, but they usually have a network, meaning you pay more or nothing at all if you see an out-of-network provider.
If you have Original Medicare (Parts A and B), you may want to buy a Medigap policy, which is supplemental insurance sold by private companies. Medigap helps pay the deductibles, coinsurance, and copays that Medicare does not cover. Medigap premiums vary widely depending on the plan and your age, and you buy it separately from Medicare.
Preventive Services You Get at No Cost
Medicare covers a long list of preventive services with no copay or coinsurance when you see an in-network provider. These include an annual wellness visit where your doctor reviews your health history and checks your blood pressure. They include cancer screenings: mammograms for breast cancer, colonoscopy or other tests for colorectal cancer, and PSA tests for prostate cancer. They include bone density screening, diabetes screening, and cardiovascular screening.
Vaccines are covered at no cost: flu vaccine once a year, pneumococcal vaccine (the schedule depends on your age and health), and shingles vaccine. If you have diabetes, Medicare covers diabetic shoes and supplies. If you have heart disease, Medicare covers cardiac rehabilitation. The key is that these services must be ordered by your doctor and provided by an in-network provider — if you go out of network, you may pay more.
Frequently Asked Questions
Does Medicare cover my medications?
Part D covers prescription drugs, but each plan has a different list of covered medications called a formulary. Your medication might be covered at a low copay, a high copay, or not covered at all depending on which plan you choose. You can search the Medicare website to see which plans cover your specific medications and what you would pay.
What happens if I need care outside the United States?
Original Medicare (Parts A and B) does not cover care outside the U.S. except in very limited cases — for example, if you are in Canada or Mexico and need emergency care. Medicare Advantage plans (Part C) vary — some offer limited coverage outside the U.S., but most do not. If you travel internationally, you may want to buy travel health insurance.
Does Medicare cover physical therapy?
Part B covers physical therapy when ordered by your doctor. You pay your 20% coinsurance after you meet your deductible. There is a limit on how many visits Medicare covers per year, though your doctor can request more visits if medically necessary. The limit changes, so ask your doctor how many visits your condition typically requires.
Will Medicare cover my stay in a nursing home?
Part A covers up to 100 days in a skilled nursing facility if you were hospitalized for at least three days first. Skilled nursing means medical care and rehabilitation, not just help with daily activities. If you need only personal care — help bathing, dressing, or eating — Medicare does not cover it, and you pay out of pocket or Medicaid covers it if you may have access to.
Can I see any doctor I want with Medicare?
With Original Medicare (Parts A and B), yes — there is no network, and any doctor who accepts Medicare can treat you. With Medicare Advantage (Part C), usually no — most plans have a network of doctors and hospitals, and you pay more or nothing at all if you see an out-of-network provider. Check your plan's provider list before you choose a plan.