Medicare Explained: Your Complete 2026 Guide

What Is Medicare and Who Does It Cover?

Medicare is the federal health insurance program run by the Centers for Medicare & Medicaid Services (CMS). It was created in 1965 and today covers more than 65 million Americans. If you are 65 or older and a U.S. citizen or lawful permanent resident who has lived in the country for at least five continuous years, you are eligible. People under 65 may also qualify if they have received Social Security Disability Insurance (SSDI) for 24 months, or if they have End-Stage Renal Disease (ESRD) or ALS.

Medicare does not work like most employer health plans. Instead of one combined plan, Medicare is built from separate 'parts,' each covering a different type of care. Understanding what each part does — and what it costs — is the first step to making smart choices about your coverage.

The Four Parts of Medicare: A, B, C, and D

Part A is Hospital Insurance. It covers inpatient hospital stays, skilled nursing facility care after a qualifying hospital stay, some home health services, and hospice care. Most people pay no monthly premium for Part A if they or their spouse worked and paid Medicare taxes for at least 10 years (40 quarters). In 2026, the Part A deductible is $1,736 per benefit period. Important: that is a per-stay deductible, not an annual one — if you are hospitalized more than once, a new deductible may apply each time.

Part B is Medical Insurance. It covers doctor visits, outpatient services, preventive care, lab work, durable medical equipment, and some home health care. In 2026, the standard monthly premium is $202.90 and the annual deductible is $283. After the deductible, Medicare typically pays 80% of the approved amount, leaving you responsible for the remaining 20% — with no out-of-pocket cap under Original Medicare. Part C (Medicare Advantage) is an alternative way to get your Medicare benefits through a private insurer, and Part D covers prescription drugs.

Original Medicare vs. Medicare Advantage (Part C)

Original Medicare — Parts A and B directly through the federal government — gives you broad access to any doctor or hospital that accepts Medicare anywhere in the country. There are no network restrictions and no referral requirements to see specialists. The trade-off is cost exposure: without a supplement plan, you pay 20% of most outpatient costs indefinitely, with no annual cap.

Medicare Advantage, also called Part C, lets you receive all your Part A and Part B benefits through a private health insurance company approved by Medicare. Most Advantage plans also bundle Part D drug coverage and include extra benefits like dental, vision, and hearing — things Original Medicare does not cover. The trade-off is that most Advantage plans use provider networks (HMO or PPO), so you may need to see in-network doctors or get referrals. Plan availability varies by location. You can compare plans in your area at Medicare.gov.

Medigap: Filling the Gaps in Original Medicare

If you choose Original Medicare, a Medigap policy (also called Medicare Supplement Insurance) can help cover costs that Medicare leaves behind — like the 20% coinsurance and, in some cases, foreign travel emergencies. Medigap plans are sold by private insurers and are standardized into lettered plans (Plan G and Plan N are among the most popular). Every insurer selling Plan G must offer the same core benefits — the only difference is price and service.

The best time to buy a Medigap policy is during your six-month Medigap Open Enrollment Period, which starts the month you turn 65 and are enrolled in Part B. During this window, insurers cannot deny you coverage or charge more due to pre-existing conditions. You cannot have both a Medigap policy and a Medicare Advantage plan at the same time.

Medicare Part D: Prescription Drug Coverage

Part D plans cover prescription drugs and are offered through Medicare-approved private insurers. If you have Original Medicare, you add Part D as a stand-alone plan. If you have Medicare Advantage, drug coverage is usually bundled in. Each Part D plan has a formulary — a list of covered drugs organized into tiers — so it is important to check whether your specific medications are covered before choosing a plan.

In 2026, a change from the Inflation Reduction Act continues to shape Part D: annual out-of-pocket drug costs are capped, giving people with high drug expenses meaningful protection. Missing your Part D enrollment window without having other creditable drug coverage can trigger a late enrollment penalty added to your monthly premium for as long as you have Part D.

When to Enroll: Key Medicare Enrollment Periods

Getting the timing right matters — missing a window can mean gaps in coverage or permanent late penalties. Your Initial Enrollment Period (IEP) is a 7-month window: it starts 3 months before your 65th birthday month, includes your birthday month, and ends 3 months after. If you or your spouse are still working and covered by an employer group health plan, you may qualify for a Special Enrollment Period (SEP) to sign up later without penalty — confirm with Social Security (SSA.gov) before delaying.

Every year, the Annual Enrollment Period (AEP) runs October 15 through December 7. During AEP, anyone on Medicare can switch between Original Medicare and Medicare Advantage, change Advantage plans, or join, switch, or drop a Part D plan. Changes take effect January 1. A separate Medicare Advantage Open Enrollment Period runs January 1 through March 31.

How to Choose the Right Medicare Coverage

There is no single 'best' Medicare plan — the right choice depends on your health needs, budget, doctors, and where you live. Start by listing your regular prescriptions, your preferred doctors and specialists, and any upcoming procedures. Then ask: do those providers accept Original Medicare? Are they in-network for any Advantage plan you are considering? If you travel frequently, Original Medicare with a Medigap plan may give you more flexibility. If you want predictable copays and extra benefits and are comfortable with a network, Medicare Advantage may save you money.

Use the official Plan Finder tool at Medicare.gov to compare Advantage and Part D plans available in your ZIP code — it shows premiums, deductibles, drug costs, and star ratings. If you want personal guidance, a licensed insurance agent or a State Health Insurance Assistance Program (SHIP) counselor can walk you through your options at no cost.