Which Part of Medicare Covers What You Need

Medicare has four 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, and medical equipment. Part D covers prescription drugs. Part C, also called Medicare Advantage, is an alternative way to get Parts A and B through a private insurance company, usually bundled with Part D.

Most people turning 65 are automatically enrolled in Part A and Part B. Part D and Part C are optional — you choose whether to add them, and the choice you make affects your costs and which doctors and pharmacies you can use. Understanding what each part covers helps you figure out which combination makes sense for your situation and budget.

Key Takeaways

• Part A covers hospital and skilled nursing stays; Part B covers doctor visits and outpatient services; Part D covers prescription drugs; Part C is a private alternative to Parts A and B.
• You are automatically enrolled in Parts A and B at 65, but you must actively choose Part D during your enrollment window or pay a penalty later if you need it.
• Part C (Medicare Advantage) replaces Parts A and B with a private plan and usually includes Part D, but limits you to in-network doctors and may require prior approval for some services.
• Original Medicare (Parts A and B) lets you see any doctor who accepts Medicare, but you pay a percentage of costs after your deductible; Advantage plans have fixed copays but narrower networks.

Part A: Hospital and skilled nursing coverage

Part A covers inpatient hospital stays, including room, meals, and standard nursing care. It also covers up to 100 days in a skilled nursing facility if you are admitted after a hospital stay of at least three days. A skilled nursing facility is not a regular nursing home — it provides intensive medical care and rehabilitation, like physical therapy after a hip replacement.

Part A also covers hospice care if you have a terminal illness, and some home health services when ordered by your doctor. You pay nothing for Part A if you or your spouse paid Medicare taxes for at least 10 years while working. If you did not, you can buy Part A, but the cost varies based on how many years you worked.

Part A has a deductible each time you are admitted to the hospital — currently different amounts depending on the length of stay — and you pay coinsurance (a percentage of costs) for longer stays. These amounts change each year.

Part B: Doctor visits and outpatient services

Part B covers doctor office visits, preventive care like annual wellness visits and cancer screenings, lab tests, X-rays, and outpatient surgery. It also covers durable medical equipment like wheelchairs, walkers, and oxygen supplies when your doctor prescribes them.

You pay a monthly premium for Part B, a yearly deductible, and then 20 percent of the cost of most services after you meet the deductible. This means your costs can vary a lot depending on how many doctor visits and tests you have. If you delay signing up for Part B after you turn 65 and do not have other health coverage, you may owe a penalty for each month you were not enrolled.

Part B does not cover routine dental, vision, or hearing care — those are separate and not part of any Medicare plan unless you buy a supplemental plan that adds them.

Part D: Prescription drug coverage

Part D covers prescription medications at pharmacies. You choose a Part D plan from private insurance companies, and each plan has a different list of covered drugs, different copays, and different pharmacies. The plan you pick affects how much you pay for your specific medications.

Part D has an enrollment window when you first turn 65. If you do not sign up then and you do not have other drug coverage, you pay a penalty for each month you go without it — even if you do not take any medications. The penalty stays with you for as long as you have Medicare.

Part D plans have a coverage gap (sometimes called the "donut hole") where you pay more out of pocket once you and your plan have spent a certain amount on drugs. After you spend enough out of pocket, catastrophic coverage kicks in and you pay less again.

Part C (Medicare Advantage): A private alternative to Parts A and B

Part C is sold by private insurance companies as an alternative to Original Medicare (Parts A and B). If you choose Part C, you get your hospital and doctor coverage through that private plan instead of through Medicare directly. Most Part C plans include Part D (drug coverage) automatically.

Part C plans often have lower monthly premiums than Original Medicare plus a supplemental plan, and they usually have fixed copays instead of percentages. However, they limit you to doctors and hospitals in their network, and many require you to get approval from the insurance company before certain services — a process called prior authorization.

Part C plans also have a yearly out-of-pocket maximum, which means your costs stop once you have paid that amount. Original Medicare does not have an out-of-pocket cap, so your costs can keep rising if you have a lot of medical needs.

Supplemental insurance (Medigap): Filling the gaps in Original Medicare

If you choose Original Medicare (Parts A and B), you can buy a supplemental plan, called Medigap, from a private insurance company. Medigap covers some or all of the deductibles, copays, and coinsurance that Original Medicare does not pay. Different Medigap plans cover different amounts — some cover almost everything, and some cover less.

Medigap plans are standardized, meaning Plan G from one company covers the same things as Plan G from another company, though the premium may differ. You do not choose what each plan covers; you choose which letter plan fits your budget and needs, then shop for the best price among companies offering that plan.

You can only buy Medigap during certain windows. The best time is within six months of turning 65 and enrolling in Part B, because companies cannot turn you down or charge you more based on your health during that window. After that window closes, they can deny you or charge more if you have health problems.

How to choose between Original Medicare and Medicare Advantage

Original Medicare (Parts A and B) plus a Medigap plan gives you the widest choice of doctors and hospitals — you can see any provider who accepts Medicare. You pay a monthly premium for Part B and Medigap, a yearly deductible, and then a percentage of costs. Your total costs depend on how much medical care you use.

Medicare Advantage (Part C) has a fixed monthly premium and fixed copays, making costs more predictable. However, you must use in-network doctors, and you may need approval before certain services. Advantage plans work well if you use a lot of routine care (because copays are fixed) and if you are comfortable with a smaller network of providers.

If you have a chronic condition and see specialists regularly, check whether your doctors are in the Advantage plan's network before you enroll. If you travel a lot or move between states, Original Medicare is usually simpler because it works anywhere in the country.

Frequently Asked Questions

Do I have to take all four parts of Medicare?

No. Part A and Part B are automatic at 65, but you can turn down Part B if you have other health coverage. Part D and Part C are optional — you choose whether to add them. However, if you do not sign up for Part D or Part B when you are first may be able to access and you do not have other coverage, you will owe a penalty later.

What happens if I do not sign up for Part D when I turn 65?

If you do not have other prescription drug coverage, you will owe a penalty for each month you go without Part D. The penalty is added to your Part D premium for as long as you have Medicare, even if you sign up later. The only exception is if you have creditable coverage (drug coverage as good as Medicare's) from an employer or union.

Can I switch from Medicare Advantage back to Original Medicare?

Yes, but only during certain times. 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 to Original Medicare, you should also buy a Medigap plan during your enrollment window, or you will have higher out-of-pocket costs.

Does Medicare cover dental, vision, or hearing?

Original Medicare does not cover routine dental, vision, or hearing care. Some Medicare Advantage plans offer limited dental or vision benefits, but they are usually basic. If you need these services, you can buy separate coverage or pay out of pocket.

What is the difference between a deductible and a copay?

A deductible is the amount you pay out of pocket before Medicare or your plan starts paying. A copay is a fixed amount you pay each time you use a service — for example, $20 for a doctor visit. Original Medicare uses deductibles and percentages; Medicare Advantage plans usually use copays.