What Are the Main Parts of Medicare and What Do They Cover in 2026?

Direct Answer: The 4 Parts, in One Sentence Each

Depends on which part you mean. Medicare has four main parts in 2026: Part A covers hospital and skilled nursing care, Part B covers doctor visits and outpatient services, Part C (Medicare Advantage) bundles A and B through private insurers, and Part D covers prescription drugs. Most people get Part A free; Part B costs $202.90 a month in 2026. Together, the four parts determine what care Medicare actually pays for.

Part A: Hospital Insurance, What It Covers in 2026

Original Medicare's Part A pays for care you get as a hospital inpatient, in a skilled nursing facility after a qualifying hospital stay, through hospice, and for limited home health visits. Roughly 99% of enrollees pay no monthly premium for Part A because they or a spouse paid Medicare payroll taxes for 40 or more quarters (about 10 years). People with 30 to 39 quarters pay $311 a month in 2026, and those with fewer than 30 quarters pay $565 a month.

Even with premium-free Part A, cost-sharing applies every time you are admitted. The 2026 inpatient hospital deductible is $1,736 per benefit period, days 1 through 60 have no additional coinsurance, days 61 through 90 cost $434 a day, and lifetime reserve days beyond that cost $868 a day. Skilled nursing facility care is free for days 1 through 20, then $217 a day for days 21 through 100, after which Part A stops paying entirely.

Part B: Medical Insurance, What It Covers in 2026

Part B is the outpatient half of Original Medicare. It covers doctor visits, outpatient hospital services (the ER, observation status, outpatient surgery), preventive care like the annual wellness visit and cancer screenings, durable medical equipment (wheelchairs, walkers, oxygen), ambulance transport, outpatient mental health care, and drugs administered in a clinical setting such as chemotherapy infusions. Unlike Part A, Part B is optional but almost everyone enrolls because it carries a late-enrollment penalty for skipping it without other creditable coverage.

The standard 2026 Part B premium is $202.90 a month, up from $185.00 in 2025, and the annual deductible is $283. After the deductible, Original Medicare pays 80% of the Medicare-approved amount for most Part B services and you pay the remaining 20% coinsurance, with no annual out-of-pocket cap unless you also carry Medigap or Medicaid. Higher earners pay an income-related monthly adjustment amount (IRMAA) on top of the standard premium, based on tax returns from two years earlier.

Part C: What Medicare Advantage Adds in 2026

Medicare Advantage is the private-insurer alternative to Original Medicare. Private companies approved by Medicare bundle your Part A and Part B benefits, and most Medicare Advantage plans (MA-PD plans) also bundle Part D drug coverage, into one plan with one card. In 2026, the average Medicare Advantage premium is about $14 a month, and roughly three-quarters of enrollees pay no premium beyond the standard Part B amount.

The trade-off for lower costs and extra benefits (dental, vision, hearing, fitness programs, and sometimes meal or transportation benefits) is a provider network. Most Medicare Advantage plans are HMOs or PPOs that require you to use in-network doctors and often require referrals or prior authorization for specialists and procedures. In exchange, Medicare Advantage plans must cap your in-network out-of-pocket spending at $9,250 in 2026 ($13,900 combined in- and out-of-network), a protection Original Medicare alone does not offer.

Part D: Prescription Drug Coverage in 2026

Part D covers prescription drugs you pick up at a pharmacy, either through a standalone Prescription Drug Plan (PDP) alongside Original Medicare, or bundled into a Medicare Advantage plan. Every Part D plan uses a formulary (a list of covered drugs sorted into cost tiers), and formularies vary by plan and insurer, so the same drug can cost differently depending on which plan you pick.

The 2026 redesign under the Inflation Reduction Act (signed August 16, 2022) caps out-of-pocket drug spending at $2,100 a year; once you hit that cap, covered drugs cost $0 for the rest of the year. Insulin is capped at $35 a month regardless of what phase of the benefit you are in. Plan deductibles top out at $615 in 2026, though many plans set a lower or $0 deductible in exchange for a higher premium.

Medigap: The Standalone Supplemental Option

Medigap, also called Medicare Supplement Insurance, is not one of the four parts, but it is the other major coverage decision people on Original Medicare face. It is a standalone policy sold by private insurers that pays some or all of the deductibles, coinsurance, and copays that Parts A and B leave you owing. Medigap cannot be paired with Medicare Advantage; you choose Original Medicare plus Medigap, or Medicare Advantage, not both.

The best time to buy Medigap is your 6-month Medigap Open Enrollment Period, which starts the month you turn 65 and are enrolled in Part B; during that window, insurers must sell you any plan sold in your state at the standard rate regardless of preexisting conditions. Outside that window, most states allow medical underwriting, meaning an insurer can charge more, add a waiting period, or deny coverage based on a preexisting condition. Medigap plans are letter-labeled (A, B, D, G, K, L, M, N) and standardized, so a Plan G from one insurer covers the same benefits as a Plan G from another; only the premium differs.

What the Parts Don't Cover, and Your Alternatives

None of the four parts of Original Medicare cover routine dental, vision, or hearing care, and Part A and Part B alone cover custodial long-term care only in narrow circumstances. This is not an ACA marketplace plan bound by essential health benefits rules; Medicare has its own, narrower statutory benefit list, so gaps are common by design, not by accident.

Three common ways people fill these gaps in 2026: pick a Medicare Advantage plan that bundles dental, vision, and hearing benefits; buy a standalone dental or vision insurance policy (these are not ACA-compliant major medical plans, just limited-benefit add-ons); or, for long-term care and for beneficiaries with low income and limited assets, apply for Medicaid, which can cover nursing home care and cost-sharing that Medicare does not.

Who's Eligible and When to Enroll in Each Part

You become eligible for Parts A and B at age 65, or earlier if you have received Social Security Disability Insurance for 24 months, have ALS (no waiting period), or have end-stage renal disease (typically a 3-month wait). Your Initial Enrollment Period is a 7-month window: 3 months before your 65th birthday month, your birthday month, and 3 months after. Part C and Part D require you to already have Part A and Part B (or at least Part A for some Part D situations), and you generally enroll during the same Initial Enrollment Period or during the Annual Enrollment Period each fall.

The Medicare Annual Enrollment Period (AEP) runs October 15 through December 7, 2026, for coverage starting January 1, 2027, and lets you switch between Original Medicare and Medicare Advantage, or change Part D plans. A separate Medicare Advantage Open Enrollment Period runs January 1 through March 31, 2026, letting anyone already on a Medicare Advantage plan switch to a different MA plan or back to Original Medicare once.

How to Find a Plan That Covers What You Need

Start at medicare.gov's Plan Finder tool, where you can compare Medicare Advantage and Part D plans available in your ZIP code side by side on premium, deductible, drug formulary, and star rating. If you are deciding between Original Medicare plus Medigap versus Medicare Advantage, compare your expected doctor visits and prescriptions against each option's total annual cost, not just the monthly premium, since Original Medicare without Medigap has no out-of-pocket cap.

Does Original Medicare (Parts A and B) cover everything I need?

No. Original Medicare covers hospital and medical care but excludes routine dental, vision, hearing, and most long-term custodial care, and it has no annual out-of-pocket cap. Most people pair it with Medigap for cost protection, a Part D plan for drugs, or switch to Medicare Advantage for bundled extra benefits.

What's the difference between Medicare Advantage (Part C) and Original Medicare?

Original Medicare (Parts A and B) is run directly by the federal government, lets you see any provider who accepts Medicare, and has no out-of-pocket cap. Medicare Advantage (Part C) is run by private insurers, usually requires in-network providers, often bundles Part D and extra benefits like dental and vision, and caps your in-network out-of-pocket costs at $9,250 in 2026.

How much does Medicare Part B cost in 2026?

The standard Part B premium is $202.90 a month in 2026, and the annual deductible is $283. Higher-income beneficiaries pay an additional income-related monthly adjustment amount (IRMAA) based on tax returns from two years earlier, which can push the total monthly premium several times higher.

Do I need Medicare Part D if I have Medicare Advantage?

Usually you get it automatically. Most Medicare Advantage plans are MA-PD plans that already bundle Part D drug coverage into the same plan, so you do not enroll in a separate standalone Part D plan. A small number of Medicare Advantage plans do not include drug coverage, in which case you may be able to add a standalone PDP depending on the plan type.

What does Medigap cover that Original Medicare doesn't?

Medigap pays some or all of the out-of-pocket costs Parts A and B leave behind: the Part A deductible ($1,736 in 2026), Part A hospital coinsurance, the Part B 20% coinsurance, and sometimes the Part B deductible ($283 in 2026), depending on which lettered plan you buy. It does not cover prescription drugs, dental, vision, or hearing.

Am I eligible for premium-free Part A?

Yes, if you or your spouse paid Medicare payroll taxes for at least 40 quarters (about 10 years) of work. With 30 to 39 quarters, you pay $311 a month for Part A in 2026. With fewer than 30 quarters, the premium is $565 a month.

What happens if I don't sign up for Medicare Part B on time?

Depends on whether you have other creditable coverage. If you delay Part B enrollment without qualifying employer coverage, you may owe a late-enrollment penalty added to your premium for as long as you have Part B, and you may have to wait for the next general enrollment period to sign up.

Can I have both a Medicare Advantage plan and a Medigap policy?

No. Medigap is designed to fill gaps in Original Medicare's cost-sharing and cannot legally be sold to someone enrolled in Medicare Advantage. You choose one path: Original Medicare (Parts A and B) plus optional Medigap and Part D, or a single Medicare Advantage (Part C) plan.