Medicare supplement insurance, often called Medigap insurance, helps to pay for some of the health services that Medicare doesn't cover. Most states, with the exceptions of Massachusetts, Minnesota and Wisconsin, have 10 standardized types of Medigap plans, designated by the letters A through D, F, G, and K through N. This guide will explain the key features of Plan C.

What Is Medigap Plan C?

Until recently, Plan C was one of the two most popular Medicare supplement insurance plans on the market. That's because only Plan C and Plan F cover the deductible for Medicare Part B outpatient medical services. Enrollment in Plan C has declined now that it is no longer available to new applicants who became eligible for Medicare in 2020 or after.

It's important to note that Medigap Plan C is not the same as Medicare Part C, which is another name for Medicare Advantage plans. Available from Medicare-approved private insurance providers, Medicare Advantage plans are an alternative way to get Original Medicare benefits — along with Medicare prescription drug coverage and other additional services such as dental, vision, hearing and wellness programs — that Medicare doesn't cover.

What Does Medigap Plan C Cover?

Medicare.gov, the official federal government website for the Medicare program, lists the following benefits for Plan C:

• Part A coinsurance and hospital costs for up to an additional 365 days after you reach the limit of your Medicare benefits.

• Part B coinsurance or copayment.

• The first 3 pints of blood for a transfusion.

• Part A hospice care coinsurance or copayment.

• Skilled nursing care coinsurance.

• Part A deductible — what you must pay out of pocket before your Medicare hospitalization coverage begins.

• Part B deductible — your out-of-pocket cost before your Medicare coverage for outpatient medical services begins.

• 80% of the foreign travel exchange — the cost of care during health emergencies when you travel internationally (up to the limits of individual plans).

What Does Medigap Plan C Not Cover?

Plan C does not cover:

• Part B excess charge. Health care providers who choose not to participate in Medicare can charge up to 15% above Medicare's allowable amounts for Part B medical services.

• As with all other Medigap policies, Plan C doesn't pay for vision care, dental care, prescription drugs or long-term care.

Who Is Eligible for a Plan C Medicare Supplement?

To purchase a Plan C Medigap policy, you must have become eligible for Medicare benefits before January 1, 2020. This is because a federal law that took effect on that date prohibits insurers from selling to newly eligible Medicare consumers supplement plans that, like Plan C and Plan F, cover the Medicare Part B deductible.

Those who already have Plan C policies may keep them. If you qualified for Medicare before 2020 but decided to delay your enrollment in Part B, or you currently have a different type of Medigap plan and want to switch, you can buy Plan C from any insurer that still sells it in your area.

How Much Does Plan C Cost?

Monthly premiums for Medicare supplement policies vary widely depending on the insurance company and your location. In some cases, the insurer will also consider your age, gender, health and lifestyle in determining what to charge. A sampling by Healthline in July 2021 showed that, for a 65-year-old male non-tobacco user, monthly Plan C premiums ranged from $124 to $335 in Washington, D.C., and from $159 to $406 in Aurora, Colorado, for example.

How Does Plan C Compare to Other Medigap Plans?

Apart from being one of only two Medicare supplement plans that cover the Part B deductible, Plan C provides similar coverage to several other options. It is among eight plans that will pay 100% of your Part B coinsurance or copayment, your first three pints of blood for a transfusion, and your Part A hospice care insurance or copayment. Plan C is one of six Medigap plans that pay 100% of the Part A deductible, 100% of skilled nursing home facility care coinsurance or copayment, and 80% of the foreign travel exchange.

Compared specifically to Plan F (the other supplement plan covering the Part B deductible), the only difference in coverage is that Plan F pays the Part B excess charge, while Plan C does not.

Is Medicare Supplement Plan C a Good Fit for Me?

If you qualify to purchase a Medigap Plan C policy, here are some things to consider as you decide whether it makes sense for you:

• Do insurance companies in your area sell Plan C? You can do a search by Zip Code on the Medicare.gov site.

• What are the premium rates for Plan C policies sold in your area, and how do they compare to the cost of other options with similar coverage?

• How often do you go to the doctor or access other outpatient medical services? If you do so frequently, Plan C's payment of your Medicare Part B deductible may reduce your out-of-pocket costs significantly.

• Do you anticipate receiving much of your healthcare from providers that don't participate in Medicare? If so, the fact that Plan C won't pay the excess charges of those providers may put you at a financial disadvantage. On the other hand, if all of your providers accept Medicare payments, you won't incur those additional fees.

• Do you travel internationally? If you get sick or hurt on one of those trips, Medicare supplement Plan C will pay a large portion of the cost of your emergency care.

How Do I Get Medigap Insurance?

Private insurance companies sell Medigap plans. The easiest way to obtain Medicare supplement insurance is to apply for it during your individual six-month open enrollment period. That time window starts the first month after you've turned 65 and enrolled in Medicare Part B. You have a guaranteed right to purchase any Medigap policy available in your state, regardless of your health condition, if you apply for it during your open enrollment period. At any other time, the insurance company may use medical underwriting to decide whether to accept or reject your application, or it may charge you a higher premium because of your health status.

Your State Health Insurance Assistance Program may have information to help you compare rates between different Medigap plans and insurers, as well as other guidance for choosing a policy. In addition, Medicare.gov notes that talking with an insurance agent, looking at online information about the insurance company and checking with your state insurance department to see if there have been any complaints against it can be important steps in evaluating your options.

While it's not available to those who are newly eligible for Medicare, the comprehensive coverage of Medigap Plan C makes it an attractive option for many who can still get it. Consider whether Plan C is a good fit for your current and future healthcare needs, and look to the information in this guide to help you make your decision.