Medicare Parts Explained in plain English: what each part covers, what it costs in 2026, and the enrollment deadlines most people miss.
Free Download: Medicare in Plain English, Your Complete Guide
Enter your email and we will send it to your inbox instantly.
Last updated: July 2026
Medicare Parts Explained: Who Qualifies and How the System Works
Most people arrive at Medicare with one feeling: overwhelmed. There are four parts, multiple plan types, enrollment windows with hard deadlines, and penalties that kick in if you miss them. Understanding how Medicare parts work, before you turn 65, is one of the most practical things you can do for your retirement finances.
Medicare is the federal health insurance program for Americans aged 65 and older, and for certain younger people with qualifying disabilities or conditions. It is administered by the Centers for Medicare and Medicaid Services (CMS) and funded through payroll taxes, premiums, and general federal revenues. For the official coverage details, medicare.gov is the authoritative source.
You are generally eligible for Medicare if you:
- Are 65 or older and a U.S. citizen or permanent legal resident who has lived in the U.S. for at least 5 continuous years
- Are under 65 and have received Social Security Disability Insurance (SSDI) for 24 months
- Have End-Stage Renal Disease (ESRD) or ALS (Lou Gehrig’s disease), regardless of age
What Medicare Part A Covers
Part A is hospital insurance. Once you have all four Medicare parts explained, Part A is the one most people worry about least, and that is partly the problem, because its limits surprise people during a medical emergency.
Medicare Part A
Hospital Insurance
What it covers: Inpatient hospital stays, skilled nursing facility care (after a qualifying hospital stay), hospice care, and some home health services.
What it costs: Most people pay $0 in Part A premiums if they or their spouse worked and paid Medicare taxes for at least 10 years (40 quarters). If you have not, you will pay either $311 or $565 per month in 2026, depending on how long you or your spouse worked and paid Medicare taxes.
The deductible: Part A has a per-benefit-period deductible of $1,736 in 2026, not an annual one. Each new hospital stay that begins more than 60 days after a previous stay resets the deductible.
Key limitation: Part A does not cover long-term custodial care: the ongoing daily assistance provided in assisted living facilities or nursing homes. This is one of the most costly and common Medicare misconceptions, and we address it below, with a full breakdown in our dedicated long-term care guide.
What Medicare Part B Covers
Part B is medical insurance. It covers the everyday health services most people think of when they picture going to the doctor. Understanding what Part B covers, and what it does not, is where having the Medicare parts explained in plain terms becomes most useful for making real decisions.
Medicare Part B
Medical Insurance
What it covers: Doctor visits, outpatient care, preventive services, lab tests, durable medical equipment (wheelchairs, walkers), and some home health services.
What it costs: The standard Part B premium is $202.90 per month in 2026 for most beneficiaries, per medicare.gov. Higher-income enrollees pay more under IRMAA (Income-Related Monthly Adjustment Amount) rules. There is also an annual deductible of $283 in 2026, after which Medicare covers 80% of approved costs.
The critical gap: Part B covers 80% of approved costs. You are responsible for the remaining 20%, with no annual out-of-pocket cap. On a $100,000 procedure, that is $20,000 out of pocket. This is why most people add either a Medigap supplement policy or a Medicare Advantage plan.
All 2026 Part A and Part B cost figures sourced from medicare.gov/basics/costs/medicare-costs. These amounts change annually, so verify current figures before making enrollment decisions.
Medicare Parts C and D: Advantage Plans and Prescription Coverage
Parts C and D are where things get more nuanced, and where the Medicare Parts Explained guide earns its keep. These are the parts that involve choices between private plans, and the right answer depends on your health, your prescriptions, and where you live.
Medicare Part C
Medicare Advantage
What it is: An alternative way to receive your Medicare benefits through a private insurer approved by Medicare. Part C plans must cover everything Original Medicare (Parts A and B) covers, and most also include Part D prescription drug coverage.
What it often adds: Many Medicare Advantage plans include dental, vision, hearing, and fitness benefits not covered by Original Medicare, often at low or $0 additional premium.
The trade-off: Medicare Advantage plans use networks of providers (HMO or PPO structures). Your care must generally go through in-network doctors and facilities. Original Medicare lets you see any provider that accepts Medicare nationwide.
For a detailed side-by-side comparison, see: Medicare vs Medicare Advantage: Which Is Right for You?
Medicare Part D
Prescription Drug Coverage
What it covers: Prescription medications. Part D is sold through private insurers approved by Medicare. Each plan has its own formulary (list of covered drugs), premiums, deductibles, and copays.
What it costs: Premiums vary by plan and location. Use the Plan Finder at medicare.gov to compare Part D plans available at your zip code. Higher-income beneficiaries pay an IRMAA surcharge on top of their plan premium.
Critical rule: Enroll in Part D when you first become eligible for Medicare, even if you do not currently take prescription medications. Delaying enrollment without other creditable drug coverage triggers a permanent late enrollment penalty that follows you for life. A licensed Medicare broker can help you find a low-cost plan before that window closes.
Not sure which Part D plan covers your medications at the best price? A licensed Medicare broker can compare every plan available in your zip code for free. They are paid by the insurers, not by you.
Medigap: Filling the Gaps in Original Medicare
Original Medicare leaves significant cost exposure, particularly the unlimited 20% coinsurance under Part B. Medicare Supplement Insurance, commonly called Medigap, is private insurance designed to cover many of these out-of-pocket costs.
What Medigap covers
- Part A and B coinsurance and copays
- Part A hospital deductible
- Skilled nursing facility coinsurance
- Foreign travel emergency care (some plans)
- Part B excess charges (some plans)
What Medigap does NOT cover
- Prescription drugs (need separate Part D)
- Routine dental, vision, or hearing
- Long-term custodial care
- Private-duty nursing
- Care outside the U.S. (with limited exceptions)
Medigap plans are standardized. Plan G from one insurer covers the same benefits as Plan G from another. The difference is price and customer service. Plan G is currently the most comprehensive Medigap plan available to new Medicare enrollees, covering nearly all out-of-pocket costs except the Part B deductible.
Medicare Enrollment Deadlines and How to Avoid Permanent Penalties
With all four Medicare parts explained above, enrollment timing is the next critical piece. This is where people make expensive, permanent mistakes. Getting the timing wrong does not just cause a short-term headache: it can add hundreds of dollars to your monthly premiums for the rest of your life.
| Enrollment Window | When It Opens | What You Can Do |
|---|---|---|
| Initial Enrollment Period (IEP) | 7-month window: 3 months before your 65th birthday month, your birthday month, and 3 months after | Enroll in Parts A, B, and D for the first time |
| General Enrollment Period (GEP) | January 1 through March 31 each year | Enroll if you missed your IEP. Coverage begins July 1. Late penalty applies. |
| Special Enrollment Period (SEP) | Triggered by qualifying life events (losing employer coverage, moving, etc.) | Enroll or change plans without penalty outside standard windows |
| Annual Enrollment Period (AEP) | October 15 through December 7 each year | Switch between Original Medicare and Medicare Advantage, or change Part D plans |
| Medicare Advantage Open Enrollment | January 1 through March 31 each year | Switch Medicare Advantage plans or return to Original Medicare |
Part B Late Enrollment Penalty
10% per year of delay (permanent)
For every 12-month period you delay Part B without qualifying coverage, your premium increases by 10%, permanently. A few years of delay adds meaningfully to your monthly bill for the rest of your life. Across a long retirement, what started as a missed deadline compounds into a significant sum in unnecessary extra premiums, and it is simple to avoid if you enroll on time.
Key exception: If you have active employer-sponsored health coverage through your own current employer (or a spouse’s), you may delay Part B without penalty. The word “current” matters: retiree coverage, COBRA, and marketplace plans do not qualify.
Part D Late Enrollment Penalty
1% per month of delay (permanent)
For every month you go without Part D or other creditable prescription drug coverage, you owe a 1% premium penalty added permanently to your Part D plan cost. A 24-month delay means your Part D premium is 24% higher for life. Even if you take no medications today, a licensed Medicare broker can help you find a low-cost Part D plan to protect yourself at no cost to you. The penalty is not worth the few dollars you save skipping it.
Track Your Enrollment Status in One Place
The Medicare Coverage Planner worksheet in the Retirement Roadmap Workbook has a simple checklist for whether you’re enrolled in Part A, B, D, Medigap, and Medicare Advantage, plus a reference page for the enrollment deadlines covered above so you always know your next window.
See the Workbook → $47 · 138 pages · softcover
What Medicare Does Not Cover: The Gaps That Catch People Off Guard
With the Medicare parts explained, the next thing most people need is a clear accounting of what Medicare does not pay for. This is where the real financial planning begins, because the gaps are significant and the costs fall entirely on you or your family.
The biggest misconception: Medicare covers long-term custodial care, the kind of ongoing daily assistance provided in assisted living communities or nursing homes. It does not. Medicare only covers skilled nursing facility care after a qualifying hospital stay, and only for a limited time with real coinsurance costs once that window runs out. For the full breakdown of the 100-day SNF rule, what Medicare Advantage and the GUIDE dementia program can help with, and what actually pays for long-term care (Medicaid, LTC insurance, VA benefits), see our guide: Does Medicare Cover Long-Term Care?
Original Medicare also does not cover routine dental, vision, or hearing care under most circumstances. These are common, recurring costs that catch new enrollees off guard. For the complete list of coverage gaps and what actually fills them, see our full guide: What Does Medicare Not Cover?
| Care Type | Typical Monthly Cost | Medicare Coverage |
|---|---|---|
| Assisted Living | $6,200/month national median | Not covered |
| Memory Care | $8,019/month national median, standalone facility (SeniorLiving.org) | Not covered |
| In-Home Personal Care | $35/hour national median | Not covered unless medically skilled |
| Routine Dental, Vision, Hearing | Varies | Not covered under Original Medicare |
Assisted living, memory care, and in-home care figures are based on the Genworth/CareScout Cost of Care Survey 2025. Costs vary significantly by location. See our full guide: Assisted Living Costs: 7 Essential Numbers Families Miss.
Exploring senior housing options? Our Senior Living Options guide covers all types of senior living, including costs, who each type is right for, and exactly what Medicare does and does not cover in each setting.
How to Choose the Right Medicare Coverage
No overview of the Medicare Parts Explained guide can make this decision for you. The right plan depends on your health, your prescriptions, your finances, your providers, and where you live.
In broad terms, Original Medicare plus Medigap tends to fit people who want the flexibility to see any Medicare-accepting provider nationwide and are willing to pay more each month for predictable, capped costs. Medicare Advantage tends to fit people who are generally healthy, want dental, vision, and hearing coverage bundled in, and are comfortable working within a plan’s network. For the full side-by-side comparison and a closer look at which one fits your specific situation, see our guide: Medicare vs Medicare Advantage: 5 Differences That Cost You.
Six months from now, this can already be behind you. Your plan is chosen, your enrollment is confirmed, your prescriptions are covered. You are not exposed to the uncapped 20% coinsurance, you are not carrying a late-enrollment penalty, and you are not making this decision under pressure during a health event. That is what getting Medicare right feels like, and it is completely achievable with the right guidance.
Medicare Parts Explained: Key Takeaways
- Part A covers hospital stays; most people pay $0 in premiums if they have 10 years of Medicare tax contributions
- Part B covers doctor visits and outpatient care, $202.90 per month in 2026 for most people, with an uncapped 20% coinsurance gap
- Part C (Medicare Advantage) bundles A, B, and usually D through a private insurer, with network restrictions
- Part D covers prescriptions; enroll even if you take no medications to avoid a permanent late penalty
- Late enrollment penalties for Parts B and D are permanent and can cost thousands of dollars over a retirement
- Medicare does NOT cover long-term custodial care in assisted living or nursing homes
- An independent Medicare broker can compare all plans in your area at no cost to you
Frequently Asked Questions
Can I keep my employer health coverage and Medicare at the same time?
Yes, if you are still working and have active coverage through your own employer (or a spouse’s employer) with 20 or more employees, you can often delay Part B without a penalty until that coverage ends. The key word is active: retiree coverage, COBRA, and marketplace plans do not count as qualifying coverage for this exception. A licensed Medicare broker can help you confirm whether your specific plan qualifies.
Does everyone pay $170 for Medicare Part B?
No. The standard Part B premium is $202.90 per month in 2026 for most beneficiaries, per medicare.gov. People with higher incomes pay more under IRMAA rules. The surcharge kicks in at individual incomes above $109,000 (2026 threshold, subject to annual adjustment). People with very low incomes may qualify for programs that help pay Part B premiums. Check medicare.gov for current premium amounts and income thresholds each year.
What if I already have prescription drug coverage through another plan?
If that coverage is considered creditable, meaning it pays at least as much as a standard Medicare Part D plan, you can delay Part D enrollment without a penalty for as long as you keep it. Your plan is required to tell you each year whether your coverage counts as creditable. If you are not sure, a licensed Medicare broker can help you check before you decide, using the Plan Finder at medicare.gov to compare options in the meantime.
What is the difference between Medicare and Medicaid?
Medicare is a federal health insurance program primarily for people 65 and older, funded through payroll taxes and premiums. Medicaid is a joint federal-state program for people with low income and limited assets, available at any age. They serve different populations with different eligibility rules. Notably, Medicaid does cover long-term custodial care in nursing homes for those who qualify financially. Medicare does not. If your income is low enough, you may qualify for both programs at the same time, which is called being “dual eligible.”
Free Download: Medicare in Plain English, Your Complete Guide
A plain-English breakdown of all four parts, enrollment deadlines, and the gaps most people miss. Enter your email and we will send it instantly.
Medicare and Health Insurance: All Guides
- What Does Medicare Part A Cover? 7 Critical Facts and Gaps
- What Does Medicare Part B Cover? 7 Critical Facts and Gaps
- Medicare vs Medicare Advantage: 5 Differences That Cost You
- What Is a Medicare Advantage Plan? 7 Answers Made Simple
- What Does Medicare Not Cover? 7 Critical Gaps Seniors Miss
- Does Medicare Cover Long-Term Care? 5 Complete Answers Made Easy
- Does Medicare Cover Home Health Care? 7 Key Coverage Rules
- Medicare HMO vs PPO: 5 Simple Facts to Avoid Mistakes
Content on SetToRetire.com is researched and drafted with AI assistance, then reviewed and edited for accuracy by the editorial team at Senior Media Group LLC. It is provided for general informational purposes only and does not constitute medical, legal, or financial advice. Consult a qualified financial or tax professional before making decisions. For more on how we create content, see our Editorial Process.