Medicare Part C (Medicare Advantage): How It Works
Last updated 06/02/2026 by
Ante Mazalin
Edited by
Andrew Latham
Summary:
Medicare Part C, commonly called Medicare Advantage, is a type of Medicare health plan offered by private insurance companies approved by the federal government that bundles Medicare Part A and Part B coverage into a single plan, often with additional benefits not covered by Original Medicare.
It differs from traditional Medicare in three key ways.
- Private plan administration: Medicare Advantage plans are run by private insurers rather than the federal government, meaning coverage rules, networks, premiums, and cost-sharing vary by plan and location.
- Bundled coverage: Most Medicare Advantage plans combine hospital, outpatient, and often prescription drug coverage into one plan, replacing the need for separate Part A, Part B, and Part D enrollment.
- Extra benefits: Many plans include dental, vision, hearing, fitness, and transportation benefits that Original Medicare does not cover, though these extras vary significantly between plans.
Roughly half of all Medicare-eligible Americans are enrolled in a Medicare Advantage plan, according to the Kaiser Family Foundation.
Whether it is the right choice depends heavily on your health needs, preferred doctors, prescription drugs, and how much cost predictability matters to you.
Medicare Part C vs. Original Medicare
Original Medicare consists of Part A (hospital insurance) and Part B (outpatient and medical services). Medicare Advantage replaces these with a private plan that must cover everything Original Medicare covers, but may do so through a network of providers with different cost-sharing structures.
| Feature | Original Medicare (Parts A and B) | Medicare Advantage (Part C) |
|---|---|---|
| Plan administrator | Federal government | Private insurer approved by CMS |
| Provider network | Any doctor or hospital that accepts Medicare | Network-restricted (HMO or PPO in most plans) |
| Prescription drug coverage | Requires separate Part D enrollment | Most plans include Part D coverage |
| Out-of-pocket maximum | No annual cap | Required annual out-of-pocket maximum |
| Dental, vision, and hearing | Not covered | Often included as extra benefits |
| Referrals required | No | Often yes (HMO plans) |
| Monthly premium | Part B premium (plus Part A if not premium-free) | Part B premium plus plan premium (some plans: $0) |
One of the most significant structural advantages of Medicare Advantage is the required annual out-of-pocket maximum, which limits total cost exposure in a given year. Original Medicare has no such cap, meaning a serious illness can generate unlimited cost sharing.
Types of Medicare Advantage plans
Medicare Advantage plans come in several structures. The type affects which providers you can see and whether you need referrals.
- Health Maintenance Organization (HMO): Requires using in-network providers for all non-emergency care. A primary care physician coordinates your care and provides referrals to specialists. Out-of-network care is generally not covered except in emergencies.
- Preferred Provider Organization (PPO): Allows out-of-network care at a higher cost-sharing level. No referral required to see specialists. More flexibility than an HMO but typically higher premiums.
- Private Fee-for-Service (PFFS): You may see any provider who accepts the plan’s payment terms. Coverage terms are set by the plan rather than a traditional network.
- Special Needs Plans (SNP): Tailored for people with specific chronic conditions, those who are dual-eligible for Medicare and Medicaid, or those living in institutional settings. SNPs offer coordinated care specific to those populations.
- Medicare Medical Savings Account (MSA): Combines a high-deductible plan with a Medicare-funded savings account. The account can be used to pay medical expenses before the deductible is met.
How Medicare Advantage enrollment works
To enroll in Medicare Advantage, you must already be enrolled in Medicare Parts A and B and live in the plan’s service area. You continue to pay your Part B premium, plus any additional premium the plan charges, which ranges from $0 to several hundred dollars per month, depending on the plan.
According to the Centers for Medicare and Medicaid Services, enrollment windows include the Initial Enrollment Period when you first become Medicare-eligible, the Annual Enrollment Period (October 15 through December 7 each year), and the Medicare Advantage Open Enrollment Period (January 1 through March 31) if you want to switch or return to Original Medicare.
Pro Tip
Before enrolling in a Medicare Advantage plan, verify that your current doctors and preferred hospitals are in the plan’s network — and check the plan’s formulary to confirm your prescription drugs are covered at a cost you can manage. Network and formulary changes happen annually, so even if you are already enrolled in a Medicare Advantage plan, review both during the annual enrollment period every October. A plan that covered your specialists and medications this year may not cover them the same way next year.
Medicare Advantage costs: premiums, deductibles, and copays
Cost-sharing under Medicare Advantage is more varied than Original Medicare because each private plan sets its own rates within CMS guidelines. What you actually pay depends on the specific plan you choose.
| Cost Type | How It Works in Medicare Advantage |
|---|---|
| Monthly premium | Ranges from $0 to $200+ per month, depending on the plan, in addition to your Part B premium |
| Deductible | Varies by plan; some plans have $0 deductibles, others may charge up to the Original Medicare Part A deductible |
| Copays and coinsurance | Set by each plan; typically, a fixed dollar amount per visit or service |
| Out-of-pocket maximum | Required by law; in 2025, the CMS-set limit is $9,350 for in-network services and $14,000 for combined in-network and out-of-network |
| Prescription drug costs | Covered through integrated Part D benefit in most plans; formulary and tier pricing vary by plan |
Medicare Advantage vs. Medicare Supplement (Medigap)
Medicare Supplement plans (Medigap) work differently from Medicare Advantage. Medigap supplements Original Medicare by paying some or all of the cost-sharing gaps left by Parts A and B. Medicare Advantage replaces Original Medicare entirely with a private plan.
You cannot enroll in both a Medicare Advantage plan and a Medigap policy at the same time. The choice between them is one of the most important decisions Medicare-eligible individuals make. Those who prioritize provider flexibility and predictable costs often prefer Medigap combined with Original Medicare. Those who want additional benefits, an out-of-pocket maximum, and potentially lower premiums often prefer Medicare Advantage.
Good to know: If you enroll in Medicare Advantage and later want to switch back to Original Medicare, you can do so during the annual enrollment period. However, switching back does not automatically guarantee Medigap coverage. In most states, Medigap insurers can use medical underwriting outside of your initial enrollment period, which means they can charge higher premiums or deny coverage based on health status if you try to add a supplement policy after leaving a Medicare Advantage plan.
Who should consider Medicare Advantage?
Medicare Advantage tends to work best for people who are generally healthy, prefer a single integrated plan for all coverage, value the out-of-pocket maximum protection, and have doctors within the plan’s network. It is particularly appealing for those who want dental, vision, and hearing coverage built in without purchasing separate standalone policies.
Original Medicare with a Medigap supplement may be a better fit for people who travel frequently, see multiple specialists outside a single network, or have complex medical needs that require consistent access to a broad range of providers. Compare health insurance marketplace options and Medicare plan types at SuperMoney’s health insurance reviews.
Frequently asked questions
Does Medicare Part C include prescription drug coverage?
Most Medicare Advantage plans include Part D prescription drug coverage as an integrated benefit. If you enroll in a Medicare Advantage plan that includes drug coverage (called MAPD), you cannot enroll in a separate Part D plan. A small number of Medicare Advantage plans do not include drug coverage; in that case, you would need to enroll in a standalone Part D plan to get prescription coverage.
Can I see any doctor with Medicare Advantage?
It depends on the plan type. HMO plans generally restrict coverage to in-network providers except for emergencies. PPO plans allow out-of-network care but typically at a higher cost-sharing level. If access to a specific specialist or hospital is important to you, confirm they are in-network before enrolling in any HMO plan.
What happens if I need emergency care outside my Medicare Advantage plan’s network?
Medicare law requires all Medicare Advantage plans to cover emergency and urgently needed care anywhere in the United States, regardless of network. You cannot be denied emergency care for being out-of-network. Cost-sharing for emergency care is also limited — plans cannot charge more for out-of-network emergency care than they would for the same care in-network.
Is Medicare Advantage available everywhere?
Medicare Advantage plans are available in most U.S. counties, but plan availability varies significantly by location. Rural areas often have fewer plan options than urban and suburban areas. You can compare available plans in your ZIP code at Medicare.gov using the Plan Finder tool during the annual enrollment period.
Related reading on Medicare and health coverage
- Medicaid — the government health program for low-income individuals, which coordinates with Medicare for dual-eligible beneficiaries who qualify for both programs.
- Out-of-pocket maximum — the annual cap on what you pay before insurance covers 100%, a key advantage Medicare Advantage has over Original Medicare.
- Deductible — the amount you pay before your plan starts covering costs; deductibles vary widely across Medicare Advantage plans.
- Copay — the fixed dollar amount you pay per visit or service under most Medicare Advantage plans, as opposed to the percentage-based coinsurance common in Original Medicare.
- Marketplace health insurance — the ACA exchange coverage used by those under 65, which transitions to Medicare at age 65 for eligible beneficiaries.
Key takeaways
- Medicare Part C (Medicare Advantage) is a private insurance alternative to Original Medicare that must cover everything Parts A and B cover, and often includes additional benefits.
- Medicare Advantage plans are required to have an annual out-of-pocket maximum; Original Medicare does not have one.
- Most Medicare Advantage plans bundle prescription drug coverage; Original Medicare requires a separate Part D enrollment.
- HMO plans restrict you to a provider network; PPO plans allow out-of-network care with higher cost sharing.
- You cannot hold a Medicare Advantage plan and a Medigap supplement simultaneously — it is one or the other.
- Enrollment is available during the Annual Enrollment Period (October 15 through December 7) and the Medicare Advantage Open Enrollment Period (January 1 through March 31).
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