Medicare 101: Understanding Your Options

Medicare can feel like alphabet soup — Part A, Part B, Part C, Part D, and deadlines that seem designed to trip you up. But once you see how the pieces fit together, it’s much simpler than it looks. This guide covers what each part does, what it costs in 2026, when to sign up, and the mistakes that cost people real money.

What Medicare Is (and Who Gets It)

Medicare is the federal health insurance program for Americans 65 and older — you’ve been paying into it through payroll taxes your whole working life. Some younger people qualify too, generally after 24 months of Social Security disability benefits or with certain serious conditions.

One thing that surprises many people: Medicare is not free, and it doesn’t cover everything. It’s a foundation you build on, not a blank check.

The Four Parts, in Plain English

Part A: Hospital Insurance

If you or your spouse worked and paid Medicare taxes for at least 10 years (40 quarters), Part A costs you nothing in monthly premiums. That covers most people. If you worked fewer than 30 quarters, you can still buy in — up to $565 a month in 2026.

Premium-free doesn’t mean cost-free, though. In 2026, a hospital stay comes with a $1,736 deductible per benefit period. Stay longer than 60 days and daily coinsurance kicks in: $434 a day for days 61 through 90, and $868 a day if you dip into your lifetime reserve days after that. A skilled nursing facility stay costs $217 a day for days 21 through 100. Those numbers are why many people add extra coverage — more on that below.

Part B: Medical Insurance

Part B covers the everyday side of health care: doctor visits, lab work, outpatient procedures, preventive screenings, and medical equipment like walkers and wheelchairs.

The standard premium in 2026 is $202.90 a month (up from $185.00 in 2025), usually deducted right from your Social Security check. The annual deductible is $283, and after that Medicare generally pays 80% of approved costs — you pay the other 20%, with no upper limit unless you have supplemental coverage.

Higher incomes pay a surcharge, called IRMAA, starting above $109,000 in modified adjusted gross income for a single filer or $218,000 for a couple filing jointly. It’s based on your tax return from two years ago — so if your income has dropped since then (say, you retired), you can ask Social Security to reconsider.

Part C: Medicare Advantage

Part C isn’t extra coverage — it’s a different way to get Parts A and B. Private insurers bundle everything into one plan, usually with drug coverage and often with extras like dental, vision, and hearing. Premiums vary by plan, and some are quite low — but you keep paying your Part B premium either way.

The trade-off is usually a network: you may need to use the plan’s doctors and hospitals, and get referrals or prior approval for some care. We compare Medicare Advantage and Original Medicare in detail in a separate guide.

Part D: Prescription Drug Coverage

Part D plans are sold by private companies and cover prescription drugs. Premiums vary by plan, and each plan has its own list of covered drugs (called a formulary) — so check that your medications are covered before you pick one.

Here’s the good news: as of 2026, your out-of-pocket spending on covered drugs is capped at $2,100 for the year. Once you hit that, the plan pays 100% for the rest of the year.

Enrollment Windows: The Part to Get Right

If you remember one thing from this guide, make it this section. Missing an enrollment window is the single costliest Medicare mistake, because the penalties last for life.

Your Initial Enrollment Period

You get a 7-month window built around your 65th birthday: the 3 months before your birthday month, your birthday month itself, and the 3 months after. So if you turn 65 in June, your window runs March 1 through September 30. Sign up in the 3 months before your birthday month if you can — it’s the surest way to have coverage in place the month you turn 65.

If you’re already receiving Social Security when you turn 65, you’ll usually be enrolled in Parts A and B automatically. If you’re not, you have to sign up yourself at SSA.gov — nobody sends a reminder.

Still Working at 65? You May Be Able to Wait

If you (or your spouse) are still working and covered by that employer’s health plan, you generally don’t need Part B yet — and you won’t be penalized for waiting. When the job or the coverage ends, you get a Special Enrollment Period: 8 months to sign up for Part B without penalty.

Two cautions. First, this applies to current employer coverage — COBRA and retiree health plans don’t count, and waiting because you have them can trigger penalties. Second, the rules can differ for smaller employers, so check with your benefits office or call 1-800-MEDICARE before deciding.

Missed Your Window? The General Enrollment Period

If you miss your Initial Enrollment Period and don’t qualify for a Special Enrollment Period, you can sign up during General Enrollment, January 1 through March 31 each year. Coverage starts the month after you sign up — which can mean months without coverage in the meantime.

The Penalties (This Is Why Deadlines Matter)

• Part B late penalty: Your premium goes up 10% for each full 12-month period you were eligible but didn’t sign up — and you pay that higher premium for the rest of your life. Wait three years, and you’re paying roughly 30% extra every month, forever.
• Part D late penalty: Go without drug coverage (or other “creditable” coverage, like a good employer drug plan) after becoming eligible, and you pay 1% of the national base premium for every month you waited — also for life. Even if you take no medications today, a low-cost Part D plan protects you from this penalty later.

The Windows You’ll Use Every Year

• Open Enrollment (October 15 – December 7): Anyone with Medicare can switch between Original Medicare and Medicare Advantage, change Advantage plans, or change Part D plans, effective January 1.
• Medicare Advantage Open Enrollment (January 1 – March 31): If you’re in an Advantage plan that isn’t working out, you can switch to a different Advantage plan or go back to Original Medicare — one change during this window.

Medigap: Filling the Gaps in Original Medicare

Original Medicare leaves you exposed to that 20% coinsurance with no cap. Medigap (also called Medicare Supplement insurance) is private insurance that picks up some or all of what Original Medicare doesn’t pay. Plans are standardized by letter — Plan G and Plan N are the most commonly chosen today — so a Plan G from one company covers the same things as a Plan G from another. Prices differ by company and location, so compare.

The critical timing rule: you get a one-time, 6-month guaranteed-issue window that starts once you’re 65 or older and enrolled in Part B. During those 6 months, insurers must sell you any Medigap plan they offer, regardless of your health. After that, they can ask health questions and turn you down in most states. If you want Medigap, that first window is by far the easiest time to get it.

5 Common Mistakes to Avoid

1. Assuming you’ll be enrolled automatically. Unless you’re already drawing Social Security, you must sign yourself up.
2. Skipping Part D because you’re healthy. The late penalty follows you for life. A low-premium plan now is cheap insurance against it.
3. Relying on COBRA or retiree coverage to delay Part B. They don’t count as employer coverage for penalty purposes.
4. Letting the Medigap window pass. After your first 6 months on Part B, buying Medigap can require passing health screening.
5. Never re-shopping your plan. Advantage and Part D plans change their costs, networks, and drug lists every year. A quick check each October can save real money.

Where to Get Free, Unbiased Help

You never have to figure this out alone — and you never have to pay for trustworthy help.

• Medicare.gov — official plan-comparison tools and cost information
• 1-800-MEDICARE (1-800-633-4227) — the official helpline, available 24/7
• SHIP (State Health Insurance Assistance Program) — free one-on-one counseling from trained, unbiased counselors in every state. Find yours at shiphelp.org.

Be careful with ads and unsolicited calls. Anyone who pressures you to enroll on the spot is selling something. The resources above are not.

Frequently Asked Questions

Do I have to sign up for Medicare if I’m still working at 65?

Not necessarily. If you have coverage through your (or your spouse’s) current employer, you can usually delay Part B without penalty, then use your 8-month Special Enrollment Period when the coverage ends. Confirm your situation with your benefits office or 1-800-MEDICARE first.

Is Part A really free?

For most people the premium is $0, if you or your spouse paid Medicare taxes for at least 10 years. But “premium-free” isn’t “free care”: in 2026 there’s still a $1,736 deductible per hospital benefit period, plus daily coinsurance on long stays.

What’s the difference between Medigap and Medicare Advantage?

They’re opposite approaches, and you can’t have both. Medigap works alongside Original Medicare, paying the costs Medicare leaves behind. Medicare Advantage replaces how you get your Medicare, bundling everything through a private plan, usually with a network.

What happens if I miss my Initial Enrollment Period?

If you don’t qualify for a Special Enrollment Period, you wait for General Enrollment (January 1 – March 31), coverage starts the month after you sign up, and you’ll likely owe the lifelong Part B late penalty — 10% for each full year you delayed.

How much will my prescriptions cost?

It depends on your plan and your medications, but there’s now a firm ceiling: in 2026, once you’ve spent $2,100 out of pocket on covered drugs, your plan pays 100% for the rest of the year. Use the plan finder at Medicare.gov to see what your prescriptions would cost under each plan in your area.