Medicare Part C combines your hospital and medical coverage into one plan

Medicare Part C, also called Medicare Advantage, is an alternative way to get your Part A (hospital) and Part B (medical) coverage. Instead of using Original Medicare and buying a separate Medigap policy, you join a private insurance plan that contracts with Medicare. That plan becomes your single source for hospital care, doctor visits, and most other covered services.

You do not have to choose Part C. Original Medicare (Part A and Part B) works fine on its own, and many people stick with it their whole retirement. Part C exists because some people prefer having one insurance card, predictable costs, and extra benefits that Original Medicare does not cover — like dental or vision — even if it means using a network of doctors.

The trade-off is real: Part C plans usually limit which doctors and hospitals you can use without paying more out of pocket. Original Medicare lets you see any doctor who accepts Medicare, anywhere in the country. If you have a doctor you want to keep, you need to check whether they are in the Part C plan's network before you enroll.

Key Takeaways

  • Medicare Part C is sold by private insurance companies and includes both hospital and medical coverage in one plan, replacing Original Medicare.
  • Part C plans often include dental, vision, or hearing coverage that Original Medicare does not, but you pay for these benefits through higher premiums or out-of-pocket costs.
  • You must use doctors and hospitals in the plan's network for the lowest cost, and going outside the network usually costs significantly more.
  • Part C is optional — you can stay on Original Medicare and buy a Medigap policy instead if you want more flexibility with your doctors.
  • You can switch between Part C and Original Medicare during the annual enrollment period each fall, so choosing Part C now does not lock you in forever.

How Part C plans work differently from Original Medicare

With Original Medicare, you have a red, white, and blue Medicare card. You can walk into any hospital or doctor's office in the country that accepts Medicare, and Medicare pays its share. You pay a deductible and coinsurance, and you can buy a Medigap policy to cover some of those costs.

With Part C, you get a different insurance card from the private plan — UnitedHealthcare, Humana, Anthem, or another company. That plan decides which doctors and hospitals are "in network." If you see an in-network provider, your costs are usually lower. If you see an out-of-network provider, you pay more — sometimes much more — or the plan may not cover the visit at all.

Part C plans also use prior authorization, which means the plan may require your doctor to get approval before certain tests, procedures, or specialist visits. This adds a step that Original Medicare does not have. Some people find this frustrating; others do not mind if it keeps costs down.

Extra benefits Part C plans often include

The main reason people choose Part C is that plans often cover services Original Medicare does not: dental cleanings and fillings, eyeglasses or contact lenses, hearing aids, fitness programs, or transportation to medical appointments. These benefits vary widely by plan and by region.

Do not assume every Part C plan includes these extras. Read the plan's benefit summary before you enroll. Some plans cover a dental cleaning once a year; others cover two cleanings plus basic fillings. Some cover one pair of eyeglasses every two years; others cover contacts instead. The value of these benefits depends on what you actually need.

Part C plans also have a yearly limit on what you pay out of pocket — called the maximum out-of-pocket limit. Once you hit that limit, the plan pays 100 percent of covered services for the rest of the year. Original Medicare has no such limit, which is one reason some people buy Medigap coverage.

When Part C makes sense for your situation

Part C works well if you are willing to use a network of doctors, you want extra coverage like dental or vision, and you prefer one insurance card and one bill. It also works well if you are healthy and do not see many specialists, because the network restrictions matter less.

Part C also makes sense if you are on a tight budget and want to know your maximum yearly costs upfront. Once you hit your out-of-pocket limit, you know the plan will cover the rest.

Part C is harder to manage if you have a chronic illness and see multiple specialists, because you need to make sure all of them are in the plan's network. It is also difficult if you travel a lot or split time between states, because many Part C plans only work in a specific region.

When Original Medicare with Medigap makes more sense

If you have a doctor you want to keep and that doctor is not in any Part C plan's network in your area, you should stay on Original Medicare. You can then buy a Medigap policy to cover the deductibles and coinsurance that Original Medicare does not pay.

Original Medicare is also better if you see many different specialists or travel frequently, because you can see any doctor anywhere without worrying about networks. Medigap policies work nationwide, so your coverage does not change if you move or spend winters in another state.

The downside is that Medigap policies do not cover dental, vision, or hearing — you would need to pay for those out of pocket or buy separate dental and vision insurance. Medigap also costs more in premiums than many Part C plans, though you have no network restrictions and no prior authorization requirements.

How to compare Part C plans in your area

Every fall, Medicare publishes a list of Part C plans available where you live. You can view them on Medicare.gov by entering your zip code. The site shows each plan's monthly premium, deductible, copays, coinsurance, out-of-pocket limit, and which doctors and hospitals are in network.

Before you compare, make a list of the doctors and specialists you see regularly. Then check whether each plan includes them in its network. A plan with a low premium is not a good deal if your main doctor is out of network.

Also compare the extra benefits. If you need dental work, check what the plan covers and whether the coverage is worth the premium you are paying. Some people find that the dental benefit alone saves them money; others find that the plan's dental coverage is too limited to matter.

Switching between Part C and Original Medicare

You can change your mind. If you enroll in Part C and later decide you want Original Medicare instead, you can switch during the Annual Enrollment Period, which runs from October 15 to December 7 each year. Your new coverage starts January 1.

There are also special circumstances that let you switch outside the enrollment period — for example, if you move out of your plan's service area, or if you lose employer coverage. If you think you may have access to for a special enrollment period, contact Medicare at 1-800-MEDICARE to ask.

If you switch from Part C back to Original Medicare, you can buy a Medigap policy at that time. Some Medigap insurers will sell to you without medical underwriting if you are switching from Part C, though this varies by company and state.

Questions to ask your doctor or Medicare counselor

Before you enroll in Part C, ask your current doctors whether they accept the specific plan you are considering. Do not just ask if they accept Medicare Advantage — ask about that particular plan, because doctors are in some plans but not others.

Ask whether your plan requires prior authorization for the tests or procedures you have had in the past year. If you have had an MRI, physical therapy, or specialist visits, ask whether the plan would have required approval first.

If you are considering staying on Original Medicare, ask your doctor whether they would recommend a Medigap policy and which type. Some doctors have experience with patients on different Medigap plans and can tell you which ones work well in their practice.

Frequently Asked Questions

Do I have to choose Part C, or can I stay on Original Medicare?

Part C is optional. You can stay on Original Medicare (Part A and Part B) your entire retirement. Many people do. If you choose Original Medicare, you can buy a Medigap policy to cover costs that Medicare does not pay. You do not need Part C to have good coverage.

What happens if my doctor leaves the Part C plan's network?

If your doctor leaves the network mid-year, the plan must usually give you notice and let you switch to Original Medicare outside the normal enrollment period. Contact your plan when ready if this happens. You may also be able to continue seeing that doctor out of network for the rest of the year at a lower cost than usual.

Can I have Part C and Medigap at the same time?

No. Part C and Medigap are two different ways to cover the same gaps in Original Medicare. You can have one or the other, but not both. If you have Part C, you do not need Medigap because Part C already includes hospital and medical coverage.

What if I move to a different state?

Most Part C plans only work in a specific region or state. If you move, your current plan may no longer cover you. You can switch to a different Part C plan in your new location, or switch to Original Medicare. You have a special enrollment period to make this change outside the normal October-December window.

How much does Part C cost compared to Original Medicare?

Part C premiums vary by plan and region. Some plans have zero monthly premium, but you still pay the Part B premium to Medicare. Other plans charge $50 to $200 or more per month. Original Medicare has no plan premium, but you pay Part A and Part B premiums, and you usually need a Medigap policy, which adds another $100 to $300 per month depending on your age and location.