Medicare Explained: A Plain-Language Guide for Turning 65

About a 9-minute read.

Key Takeaways

Medicare has four parts: A (hospital), B (doctors and outpatient), C (Medicare Advantage, a private alternative), and D (prescription drugs).

You'll pick one of two paths: Original Medicare (A + B) plus a stand-alone Part D plan and usually a Medigap policy, or a Medicare Advantage plan that bundles it together.

Your Initial Enrollment Period is a 7-month window around your 65th birthday month. Missing it without other qualifying coverage can trigger lifelong late-enrollment penalties.

For 2026, the standard Part B premium is $202.90 per month and the Part D out-of-pocket cap is $2,100.

Whichever path you choose, plan details change every year, so the choice isn't permanent and shouldn't be treated as set-and-forget.

Medicare has four parts. It has two private-plan markets, an alphabet of Medigap options, and enrollment deadlines that can raise your premiums for life. It is genuinely confusing, and the mail you will get from insurers does not help. This guide covers three things in plain language: what each part does, the two ways people put their coverage together, and the timing that matters. It is written for people approaching 65 and for the family members helping them.

Not affiliated with the federal Medicare program. PlanAlert is an independent consumer tool. For official information and enrollment, use Medicare.gov, call 1-800-MEDICARE, or contact your free State Health Insurance Assistance Program (SHIP) at shiphelp.org.

The Four Parts of Medicare, One Paragraph Each

Part A: Hospital Insurance

Part A covers inpatient hospital stays, skilled nursing care after a qualifying hospital stay, hospice, and some home health care. Most people pay no premium for Part A. You qualify for premium-free Part A if you or a spouse paid Medicare taxes for at least 10 years (40 quarters).

Part A is not free at the point of care, though. In 2026 the inpatient hospital deductible is $1,736 per benefit period, and daily coinsurance starts after 60 days (Federal Register, CY 2026, retrieved 2026-08-27).

One catch if you are still working: signing up for Part A ends your ability to contribute to a Health Savings Account (HSA). If you have an HSA, talk to your benefits administrator first.

Part B: Medical Insurance

Part B covers doctor visits, outpatient care, preventive services, lab tests, and durable medical equipment. It has a monthly premium. The standard 2026 premium is $202.90. Higher earners pay more through a surcharge called IRMAA, which starts at about $109,000 in income for an individual or $218,000 for a couple.

The 2026 Part B deductible is $283. After that, you typically pay 20% of the Medicare-approved amount for most services (Railroad Retirement Board summary of CMS figures, retrieved 2026-08-27).

Original Medicare is Parts A and B together, run by the federal government. It has no networks (any provider that accepts Medicare works), and by itself it has no out-of-pocket maximum and no drug coverage. Those two gaps are what the rest of the choices exist to fill.

Part C: Medicare Advantage

Medicare Advantage (Part C) is a private plan you choose instead of using Original Medicare directly. Medicare pays the plan to provide your Part A and Part B benefits. The plan almost always adds Part D drug coverage. It usually adds extras too, such as dental, vision, hearing, and a fitness benefit.

The trade-off: you use the plan's network. You may need referrals and prior approval for some care. The plan sets its own copays and its own yearly out-of-pocket limit.

In 2026, about 55% of eligible Medicare beneficiaries are in Medicare Advantage (35.2 million of 64.2 million). The average person can pick from 32 Medicare Advantage drug plans (KFF, retrieved 2026-08-27).

Part D: Prescription Drug Coverage

Part D covers prescription drugs. You get it either as a stand-alone plan alongside Original Medicare, or built into a Medicare Advantage plan. Every Part D plan has a formulary (its list of covered drugs and cost tiers) that changes annually. For 2026, the redesigned benefit has a standard deductible capped at $615. It also has a hard $2,100 annual out-of-pocket cap, after which covered drugs cost you nothing for the rest of the year (KFF summarizing CMS CY 2026 parameters, retrieved 2026-08-27).

2026 Medicare cost	Amount
Part B standard premium (per month)	$202.90
Part B deductible (per year)	$283
Part A inpatient hospital deductible (per benefit period)	$1,736
Part D standard deductible (maximum)	$615
Part D out-of-pocket cap (per year)	$2,100

Sources: CMS via the Railroad Retirement Board (Part B); Federal Register CY 2026 (Part A); KFF summarizing CMS CY 2026 Part D parameters. Retrieved 2026-08-27.

The Two Paths: How People Actually Build Their Coverage

Almost everyone ends up on one of two structures. The choice is usually framed as Original Medicare vs. Medicare Advantage.

	Path 1: Original Medicare + Part D + Medigap	Path 2: Medicare Advantage
Provider access	Any provider nationwide that accepts Medicare; no networks	Plan network, mostly local; referrals and prior authorization for some care
Monthly cost	Higher: Part B + Part D + Medigap premiums	Lower: often $0 plan premium beyond Part B
Out-of-pocket predictability	Very high once Medigap is in place	Varies by use, but capped by a required annual maximum
Extra benefits (dental, vision, hearing, fitness)	Generally none	Usually included
Best for	Frequent travelers, people who want maximum provider freedom or predictable costs	People comfortable with a network who want low premiums and extras

General comparison for people new to Medicare. Individual plans vary; confirm details on Medicare.gov.

Path 1: Original Medicare + Part D + Medigap

Medigap (Medicare Supplement) is a private policy that pays most of the deductibles and coinsurance Original Medicare leaves you with. On this path you keep Original Medicare (Parts A and B), add a stand-alone Part D drug plan, and add a Medigap policy on top.

Medigap plans are standardized and sold by letter. Plan G and Plan N are among the most commonly chosen by new enrollees. A "Plan G" from one insurer covers the same things as a "Plan G" from another; only the price and service differ. (Massachusetts, Minnesota, and Wisconsin standardize their Medigap plans differently.)

Path 2: Medicare Advantage (Part C)

You get your Part A, Part B, and usually Part D benefits through one private plan, often with a $0 additional premium beyond your Part B premium. The trade is the network, the prior-authorization rules, and benefits that can change every year.

The Medigap timing trap: when you first enroll in Part B at 65 you get a 6-month window to buy any Medigap plan with no medical underwriting. Miss it, and in most states insurers can later deny you or charge more based on health. That makes switching from Medicare Advantage back to Original Medicare plus Medigap harder down the road. One narrow exception: if you joined a Medicare Advantage plan when you first became eligible, you have a 12-month "trial right" to drop it and buy Medigap on a guaranteed-issue basis. Factor all of this into the first decision.

Enrollment Timing: The Deadlines That Carry Lifelong Penalties

This is where mistakes are expensive and permanent, so it is worth getting right.

Your Initial Enrollment Period (IEP)

A 7-month window: the 3 months before your 65th birthday month, your birthday month, and the 3 months after. Sign up for Part A and Part B here unless you have qualifying coverage from current employment (yours or a spouse's).

If You Keep Working Past 65

You can usually delay Part B without penalty if you or your spouse are still working and covered by an employer group plan from a company with 20 or more employees. You then get a Special Enrollment Period to sign up when that coverage ends. Rules differ for small employers and for retiree coverage, so confirm the details with the benefits administrator and with Medicare.

The Penalties for Signing Up Late

Part B: your premium rises 10% for each full 12-month period you were eligible but not enrolled, and the surcharge lasts as long as you have Part B.
Part D: a smaller penalty, roughly 1% of the "national base premium" per month you went without creditable drug coverage, also generally permanent.
General Enrollment Period: if you miss your IEP and have no Special Enrollment Period, you sign up between January 1 and March 31, with coverage starting the month after you enroll.

After You're Enrolled: The Annual Windows

Medicare Open Enrollment, October 15 to December 7: change your Advantage or Part D plan, or switch between Original Medicare and Advantage. Changes take effect January 1.
Medicare Advantage Open Enrollment, January 1 to March 31: if you are in an Advantage plan, make one switch.

This is also when the Medicare loyalty tax shows up: auto-renewing without checking what changed. The same slow creep affects ordinary household bills, where the price rises a little each year and nobody sends a warning.

How to Choose Your Path Without a Sales Pitch

Start with your doctors. List the providers and hospital you want to keep. If staying with them matters and any are not in local Advantage networks, that points toward Original Medicare plus Medigap.
List your prescriptions. Exact drugs and doses. You will enter these into the Plan Finder to compare real total costs, not just premiums.
Be honest about travel. Splitting time between states or frequent travel favors Original Medicare's nationwide access.
Do the full-year math. Add up premiums plus expected out-of-pocket costs for each option, including a bad-year scenario where you are hospitalized. For example, a $0-premium Advantage plan with a $4,000 out-of-pocket maximum can cost more in a hospitalization year than a Medigap premium of about $150 per month.
Use the free help. The Medicare Plan Finder at Medicare.gov/plan-compare is free and unbiased. SHIP counselors (shiphelp.org) give free one-on-one guidance and do not sell plans. Be wary of unsolicited calls and mailers.

Caregiver tip: sit down together with the pill bottles and insurance cards before you touch the computer. The two inputs that drive the whole decision are the current drug list and the must-keep providers. Everything else is comparison.

Your Medicare Choice Is Not Permanent, and Shouldn't Be Set-and-Forget

Whichever path you pick, you can change it during a future Open Enrollment, subject to the Medigap-underwriting caveat above. You should also review it every year. Premiums, drug formularies, provider networks, and extra benefits all reset annually. About 7 in 10 beneficiaries do not compare their coverage during Open Enrollment (KFF, retrieved 2026-08-27), which is how people drift into plans that no longer fit.

That is the gap PlanAlert is built to close. We watch the plans a household already has and send one alert when something better-matched appears. We are not paid by carriers to steer you anywhere, which is also how PlanAlert differs from bill-negotiation apps.

New to Medicare? Get your first-year decision right, then keep an eye on it. We plan to extend PlanAlert's plan monitoring to Medicare Advantage and Part D. Join the early-access list to be notified when it is available.

Frequently Asked Questions

Do I have to sign up for Medicare at 65?

If you are already receiving Social Security, you are usually enrolled in Parts A and B automatically. If not, enroll during your 7-month Initial Enrollment Period, unless you have qualifying coverage from current employment. Missing that window can mean lifelong late penalties. Part A alone is often worth taking even if you are still working, since most people pay no premium for it. The exception is an HSA: signing up for Part A ends your ability to contribute.

Is Medicare Advantage better than Original Medicare?

Neither is universally better. Medicare Advantage has lower premiums and extra benefits but uses networks and prior authorization. Original Medicare with Medigap costs more per month but offers nationwide provider access and very predictable costs. The right answer depends on your doctors, your prescriptions, your travel, and your tolerance for insurer paperwork.

What is Medigap, and do I need it?

Medigap (Medicare Supplement) is a private policy that pays most of the deductibles and coinsurance Original Medicare leaves you with. You would want it if you choose Original Medicare and do not want exposure to unlimited 20% coinsurance. You cannot have Medigap with a Medicare Advantage plan. Buy it during your six-month Medigap Open Enrollment window to avoid medical underwriting.

How much does Medicare cost in 2026?

For most people the fixed costs are: no Part A premium, a $202.90 per month standard Part B premium, and a $283 Part B deductible. On top of that you pay either a Medicare Advantage plan (often $0 extra) or a Part D plan plus a Medigap premium. Higher earners also pay IRMAA surcharges on Parts B and D.

What is Extra Help, and could my parent qualify?

Extra Help (also called the Part D Low-Income Subsidy) lowers or eliminates Part D premiums, deductibles, and copays for people with limited income and assets. People who qualify also get a continuous Special Enrollment Period, so they can change drug plans outside the normal windows. Apply through the Social Security Administration or your State Health Insurance Assistance Program (SHIP).

Can my adult child handle my Medicare enrollment?

They can research and compare plans for you and join you on calls. To enroll for you, or to speak with Medicare without you present, they need to be your authorized representative on file with the Social Security Administration or Medicare. A valid power of attorney the plan accepts also works.

The Bottom Line

Parts A and B are Original Medicare; Part C (Advantage) is a private alternative; Part D is drug coverage.
Pick one of two structures: Original Medicare + Part D + Medigap, or Medicare Advantage.
Enroll during your 7-month Initial Enrollment Period unless you have qualifying coverage from active employment; late penalties are permanent.
Review the choice every year. It is not set-and-forget, and the plan you pick this year will look different next year, which is exactly the loyalty tax.