Last Updated: September 15, 2026
Medicare is confusing largely because of its own vocabulary. Four letters, two competing ways of putting them together, and a mailbox full of advertisements that rarely explain the basics. The good news is that the underlying structure is simpler than it appears, and once the four parts make sense, the rest of the decisions become manageable.
This guide explains what each part does and how the pieces fit together. It deliberately does not quote premiums, deductibles or specific deadlines, because those figures are set annually and any number printed here would go stale. Verify every current figure and date at medicare.gov or by calling Medicare directly, and treat this as a map rather than a quote.
Quick answer: Our top pick in 2026 is the Part A — our #1 rated choice. See the full ranked comparison, alternatives and buying advice below.
Quick Verdict
Parts A and B together are what people mean by Original Medicare. Part A covers hospital care and Part B covers doctors, outpatient care and medical equipment. Part D covers prescription drugs and is bought separately. Part C, also called Medicare Advantage, is not an additional layer of benefits. It is an alternative way to receive your Parts A and B benefits, delivered by a private insurance company that usually bundles drug coverage and extras into one plan with its own network and rules.
So the real decision is a fork in the road: take Original Medicare, usually with a separate Part D plan and often with a Medigap supplement policy, or take a Medicare Advantage plan that packages things together. Neither path is correct for everyone, and the right answer depends on your health, your doctors, your medications and where you live.
| Part | Covers | How you get it | Key thing to know |
|---|---|---|---|
| Part A | Inpatient hospital stays, skilled nursing facility care after a qualifying hospital stay, hospice, some home health care | Federal government; most people qualify without a monthly premium based on their work history | Premium-free for most, but not for everyone; it does not cover long-term custodial care |
| Part B | Doctor visits, outpatient care, preventive services, lab tests, durable medical equipment such as walkers and oxygen equipment | Federal government; carries a monthly premium for everyone | Delaying it without qualifying coverage can create a lasting late penalty |
| Part C (Medicare Advantage) | Everything A and B cover, delivered through a private plan, usually with Part D and extra benefits bundled in | Private insurance companies approved by Medicare | Uses provider networks and prior authorization; you still pay the Part B premium |
| Part D | Prescription drugs | Private insurance companies, either standalone or built into a Medicare Advantage plan | Each plan has its own drug list; the same drug can be treated very differently by two plans |
| Medigap (Supplement) | Helps pay costs Original Medicare leaves to you | Private insurance; works only with Original Medicare | Cannot be combined with a Medicare Advantage plan |
How to Choose
Part A: hospital coverage you mostly earned already
Part A pays for inpatient hospital stays, care in a skilled nursing facility following a qualifying hospital admission, hospice care and some home health services. Most people have paid for it through payroll taxes over a working lifetime and owe no monthly premium for it. Two points cause confusion. First, Part A has its own cost-sharing structure for hospital stays, so “premium-free” does not mean “free”. Second, Part A does not pay for long-term custodial care, meaning ongoing help with dressing, bathing and eating in a nursing home. That is one of the biggest gaps in Medicare and it surprises many families at the worst possible moment.
Part B: the everyday medical coverage
Part B is where most routine care lives: doctor appointments, outpatient procedures, lab work, preventive screenings, mental health services and durable medical equipment. Everyone pays a monthly premium for Part B, and higher-income households pay more. Part B typically pays a share of the approved cost while you pay the rest, which is exactly why many people add either a Medigap policy or choose a Medicare Advantage plan to limit their exposure.
Durable medical equipment is worth understanding if mobility or breathing equipment is in your future. Items such as walkers, wheelchairs, hospital beds and home oxygen equipment can fall under Part B, but coverage depends on your doctor documenting medical necessity and on obtaining the equipment from a supplier that participates in Medicare. No product is automatically covered because a seller says so.
Part C: a different way to receive the same benefits
Medicare Advantage plans are offered by private insurers and must cover everything Parts A and B cover. In exchange for accepting a network of doctors and hospitals, and rules such as prior authorization for certain services, these plans often bundle in prescription coverage and extras that Original Medicare does not provide, which may include routine dental, vision, hearing or fitness benefits depending on the plan.
The trade-offs are real in both directions. Networks restrict which doctors you can see and how care works when you travel. Plan details, including which extras are offered, can change from year to year. On the other hand, the bundled structure and annual out-of-pocket maximum appeal to many people. Read the specific plan documents rather than the advertisement.
Part D: the part people underestimate
Prescription coverage is not automatic. You either choose a standalone Part D plan alongside Original Medicare or get drug coverage built into a Medicare Advantage plan. The critical detail is the formulary, the list of drugs a plan covers and what tier each one sits in. Two plans with similar premiums can treat the same medication very differently, so compare plans using your actual medication list rather than the premium alone. Medicare’s own plan finder tool at medicare.gov lets you enter your prescriptions and compare.
Medigap: only with Original Medicare
Medigap, also called Medicare Supplement Insurance, is sold by private insurers to help pay the costs Original Medicare leaves to you. Policies are standardized into lettered plans, so the same letter provides the same benefits regardless of which company sells it, although prices differ. The rule that trips people up is that Medigap works only with Original Medicare. You cannot hold a Medigap policy and a Medicare Advantage plan at the same time. There is also a protected window for buying Medigap when you first enroll in Part B, and buying outside that window may allow insurers to consider your health history in some states. This is worth understanding before you make your initial choice, because the first decision is easier to make than to reverse.
Timing matters more than almost anything else
Medicare has defined enrollment periods, and missing them can create penalties that stay with you permanently rather than for a single year. There is an initial period around your 65th birthday, a general period each year for people who missed it, special periods for particular circumstances such as losing employer coverage, and an annual window each fall to change plans. The exact dates and rules are set by Medicare and should be confirmed at medicare.gov rather than taken from any article, including this one.
The Picks in Detail
If you value choosing any doctor. Original Medicare plus a Part D plan, with a Medigap policy if the budget allows, gives you the widest access to providers who accept Medicare nationally, without network restrictions or referrals. It usually costs more in monthly premiums and less in surprises. People who travel frequently, split the year between two states, or see specialists at distant hospitals often end up here.
If you prefer one plan and one card. A Medicare Advantage plan bundles medical and usually drug coverage with an annual out-of-pocket maximum and possible extra benefits. It works best when your existing doctors are in the plan’s network and you are comfortable with the plan’s rules for referrals and authorizations. Confirm your doctors and your pharmacy are in network before enrolling, and check again each year, since networks change.
If you are still working past 65. Employer coverage can change what you should do, and the rules differ depending on the size of the employer. Talk to your employer’s benefits administrator and to Medicare before your birthday, not after. This is one of the most common sources of costly enrollment mistakes.
If money is tight. There are federal and state programs that help with Medicare costs for people with limited income and resources, including help with premiums and with prescription costs. Eligibility rules vary by state. Your State Health Insurance Assistance Program offers free, unbiased counseling and is not selling anything, which makes it a better first call than any advertisement you receive in the mail.
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FAQ
Do I have to sign up, or does it happen automatically?
It depends on your circumstances. Some people are enrolled automatically, commonly those already receiving Social Security benefits, while others must actively sign up. Because the consequences of assuming wrongly can follow you for years, confirm your own situation directly with Social Security or at medicare.gov well before you turn 65.
Can I change my mind later?
There are defined windows each year when you can switch between Medicare Advantage plans, move between Original Medicare and Advantage, or change Part D plans. The complication is Medigap: your protected right to buy a supplement policy is strongest when you first enroll, so switching back to Original Medicare years later may not come with the same protections. Check current rules before assuming a change is reversible.
What does Medicare not cover?
Notable gaps include long-term custodial care, most routine dental care, routine vision and hearing aids under Original Medicare, and care outside the United States in most situations. Some Medicare Advantage plans add some of these as supplemental benefits, which varies by plan and by year.
Is Part B optional?
Technically you can decline it, but doing so without other qualifying coverage such as active employer insurance can result in a late enrollment penalty that increases your premium for as long as you have Part B. This is one of the most expensive mistakes in Medicare and is worth a phone call before you decide.
Where can I get help that is not a sales pitch?
Medicare’s own website and helpline, and your State Health Insurance Assistance Program, provide free counseling with no product to sell. Insurance agents can be genuinely helpful, but understand they are typically paid by the plans they sell. Getting a second opinion from a non-commercial source before enrolling is time well spent.
Ready to decide? Our #1 pick for 2026 is the Part A.
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