Medicare can feel overwhelming at first. Part A, Part B, Part C, Part D, Medicare Advantage and Medigap all sound alike, and the rules around each one can be hard to follow. This guide to Medicare basics explains what each part does, how the parts fit together, when you can enroll, and which questions to ask before you choose coverage. It comes to you from Apple IPA.
Key Takeaways
- Part A covers hospital and facility care.
- Part B covers doctor visits, outpatient care and preventive services.
- Part C (Medicare Advantage) is a private-plan alternative to Original Medicare.
- Part D covers prescription drugs.
- Medigap is extra insurance that works alongside Original Medicare only.
- Your enrollment timing matters, so plan ahead.
In This Guide
- What Is Medicare?
- Part A: Hospital Insurance
- Part B: Medical Insurance
- Part C: Medicare Advantage
- Part D: Prescription Drug Coverage
- What About Medigap?
- Original Medicare vs. Medicare Advantage
- When Can You Enroll?
- Common Mistakes to Avoid
- Questions to Ask Before You Choose
- Frequently Asked Questions
What Is Medicare?
Medicare is a federal health insurance program. It is primarily for people age 65 and older. It also covers certain younger people with disabilities, and people with End-Stage Renal Disease or other qualifying conditions.
Medicare is split into parts, and each part covers a different type of care. Together, Part A and Part B make up what is called Original Medicare. Parts C and D, along with Medigap, are ways to add to or replace that foundation.
Medicare Parts at a Glance
| Part | What It Is | What It Generally Covers |
|---|---|---|
| Part A | Hospital Insurance | Inpatient hospital, skilled nursing facility, hospice, some home health |
| Part B | Medical Insurance | Doctor visits, outpatient care, preventive services, equipment |
| Part C | Medicare Advantage | Parts A and B through a private plan, often with extra benefits |
| Part D | Prescription Drug Coverage | Covered prescription medications |
| Medigap | Medicare Supplement | Helps pay some out-of-pocket costs of Original Medicare |
Medicare Part A: Hospital Insurance
Part A helps cover inpatient and facility-based care. If you are admitted to a hospital, this is the part that generally applies.
Part A generally helps cover:
- Inpatient hospital care
- Skilled nursing facility care
- Hospice care
- Certain home health care services
Many people pay no premium for Part A. This is because they or their spouse paid Medicare taxes for long enough while working. Not everyone qualifies, though, and the details depend on your work history.
Medicare Part B: Medical Insurance
Part B helps cover medically necessary services and supplies, plus many preventive services. It handles much of your day-to-day care outside the hospital.
Examples include:
- Doctor visits
- Outpatient care
- Preventive screenings
- Certain vaccines
- Durable medical equipment
- Some home health services
Medicare Part C: Medicare Advantage
Medicare Advantage, also called Part C, is another way to get your Medicare coverage. It is delivered through a Medicare-approved private health plan. You still have Medicare, but a private company administers your benefits.
These plans include Part A and Part B coverage, and most also include Part D drug coverage. Depending on the plan, they may add benefits such as dental, vision or hearing.
Things to check with any Medicare Advantage plan:
- Which doctors, specialists and hospitals are in the network
- Whether you need referrals to see specialists
- Which services require prior authorization
- What extra benefits are included, and any limits on them
- How the plan handles care when you travel
Medicare Part D: Prescription Drug Coverage
Part D helps cover prescription medications. With Original Medicare, you can generally buy a separate drug plan. Many Medicare Advantage plans already include drug coverage.
Each Part D plan sets its own premiums, formulary (its list of covered drugs), deductible and cost-sharing. Two plans can cover the same drug at very different costs, so compare plans using your actual medication list.
What About Medigap?
Medicare Supplement Insurance, called Medigap, is extra insurance that can help pay some of the out-of-pocket costs of Original Medicare, such as deductibles and coinsurance.
Medigap is not the same as Medicare Advantage. Medigap works alongside Original Medicare. Medicare Advantage replaces the way you receive your Medicare benefits. Medigap is generally not used with a Medicare Advantage plan.
Timing matters here. You get a one-time Medigap Open Enrollment Period of six months. It starts once you are 65 or older and enrolled in Part B. During this window, insurers generally cannot refuse to sell you a policy.
Original Medicare vs. Medicare Advantage
One of the biggest choices is whether to stay with Original Medicare or join a Medicare Advantage plan. Both cover the same core medical services, but they work differently.
| Feature | Original Medicare | Medicare Advantage |
|---|---|---|
| Who runs it | Federal government | Private insurance companies approved by Medicare |
| Choice of doctors | Any provider in the U.S. that accepts Medicare | Usually a plan network |
| Drug coverage | Separate Part D plan | Often built in |
| Extra benefits | Generally no routine dental, vision or hearing | May include dental, vision and hearing |
| Medigap | Can be added | Not used with these plans |
| Care abroad | Generally not covered outside the U.S. | Generally not covered, though some plans offer limited travel benefits |
Neither option is right for everyone. The better fit depends on your doctors, your medications, your health needs and how much predictability you want.
When Can You Enroll?
Most people first become eligible around age 65. The Initial Enrollment Period lasts seven months:
- The three months before the month you turn 65
- The month you turn 65
- The three months after
Other enrollment periods exist for people in different circumstances. For example, if you keep working and have coverage through your current employer, your options for when to enroll in Part B may be different.
Other Key Enrollment Windows
- Annual Open Enrollment (October 15 – December 7): Each year you can join, drop or switch Medicare Advantage and Part D plans. Changes take effect January 1.
- General Enrollment Period (January 1 – March 31): If you missed your Initial Enrollment Period, you can sign up in this window. Coverage starts the month after you sign up.
- Special Enrollment Periods: You may qualify after certain life events, such as moving or losing other coverage.
- Medigap Open Enrollment: This is a one-time six-month window, as described above.
Common Mistakes to Avoid
- Waiting too long to enroll. Missing your enrollment window can lead to gaps in coverage or added costs. Check the rules for your situation.
- Not checking your doctors. If you choose a plan with a network, confirm your providers are included first.
- Ignoring your prescription list. A plan’s formulary can change, so review it every year.
- Assuming Medigap and Medicare Advantage work together. They are two different paths.
- Skipping the annual review. Plans change benefits, networks and costs every year, and so can your health needs.
Questions to Ask Before You Choose
Knowing the parts is a good first step. Choosing or changing coverage also means weighing:
- Are my doctors, specialists and hospitals in the plan’s network?
- Are my prescriptions covered, and which pharmacies can I use?
- What are the premiums, deductibles and out-of-pocket costs?
- Do I want supplemental coverage?
- Do I need coverage when I travel?
- Does the plan require referrals or prior authorization?
Frequently Asked Questions
What is the difference between Medicare Part A and Part B?
Part A is hospital insurance. It covers inpatient hospital stays, skilled nursing facility care, hospice and some home health care. Part B is medical insurance. It covers doctor visits, outpatient care, preventive services and certain equipment.
Is Medicare Advantage the same as Medicare Supplement (Medigap)?
No. Medicare Advantage is an alternative way to get your Medicare benefits through a private plan. Medigap is extra insurance that helps pay certain out-of-pocket costs of Original Medicare.
Do I need a separate Part D plan?
If you have Original Medicare, you can generally buy a separate Part D plan. Many Medicare Advantage plans already include drug coverage.
When can I sign up for Medicare?
Most people first qualify around age 65, with a seven-month Initial Enrollment Period. There are other enrollment periods based on your circumstances.
When can I change my Medicare plan?
You can generally make changes to Medicare Advantage and Part D coverage during Annual Open Enrollment, October 15 through December 7. You may also qualify for a Special Enrollment Period after certain life events.
Need Official Answers?
Visit Medicare.gov or call 1-800-MEDICARE.
Looking for a doctor, specialist or clinic? Explore the Apple IPA provider directory to find care near you.
This article is for general informational purposes only. It is not medical, insurance, legal or financial advice. Medicare rules, benefits and costs can change. For current information about your coverage, visit Medicare.gov or contact Medicare directly. To find providers, visit appleipa.org.
