What to Know About Medigap Enrollment

Medically Reviewed by Dany Paul Baby, MD on November 25, 2022
5 min read

A Medigap plan can protect you from expensive out-of-pocket costs. Sign up during Medicare supplement open enrollment to get the lowest possible premium.

Medigap coverage — also known as Medicare Supplement Health Insurance — is a commercial health insurance policy. It pays some or all of the costs that Medicare doesn’t cover.

Medicare coverage starts at age 65 for most people. Medicare Part A covers inpatient hospital care, skilled nursing facility care, labs, hospice, surgery, and home healthcare. Medicare Part B covers most doctor visits and outpatient care.

Medicare pays for medically necessary services in all these settings. Most of the time, Medicare doesn’t pay 100% of the charge. You may owe out-of-pocket costs like deductibles, coinsurance, and copayments.

The 2023 Medicare Part A deductible will be $1,600. After you pay the Part A deductible, you owe coinsurance on any inpatient hospital charges.

The 2023 Medicare Part B deductible will be $226. After you pay the Part B deductible, you owe 20% coinsurance on any outpatient services.

For example, your doctor does a $500 procedure on you and bills your Medicare policy. You’ve already met your deductible and only owe coinsurance. Medicare will pay $400. You will owe $100 unless you have a Medicare supplement.

Medicare supplement health insurance plans generally cover any services Medicare Parts A and B approve. They pay part of all of Medicare’s coinsurance, copayments, and deductibles. 

Federal and state laws dictate the coverage rules for Medigap plans. Companies that offer Medigap plans must use standardized benefit packages that follow these laws.

Medigap plans usually don’t cover services or equipment that Medicare excludes. This includes nursing home care, vision, dental, and hearing aids.

Medigap plans don’t pay for prescription drug costs. These are covered by separate plans under Medicare Part D.

Certain Medigap plans offer more benefits than Medicare. For example, some provide medical coverage when traveling in another country.

There are 10 types of Medigap plans — A, B, C, D, F, G, K, L, M, and N. Each plan has slightly different benefits:

  • Most plans cover 100% of Medicare Part B coinsurance. Plans K and L cover less.
  • All plans cover Medicare Part A hospice coinsurance and copayments. Plans K and L cover less.
  • All plans except A and B cover skilled nursing facility care coinsurance.
  • Plan A doesn’t cover the Medicare Part A deductible. All other plans cover part or all of it.
  • Plans C, D, F, G, M, and N provide some medical coverage when traveling in other countries.
  • Plans K and L have an out-of-pocket limit that caps the amount of money they’ll pay.

You can’t select a Medigap plan that covers the Medicare Part B deductible if you’re new to Medicare. This includes plans C and F. If you bought one of these plans before 2020, you can keep it going forward.

Medicare supplement open enrollment is a period when you’re new to Medicare and eligible to sign up for a Medigap plan. It’s the best time to enroll in Medigap as insurance companies must offer you their lowest rates.

You can apply for Medigap coverage at any time once you’re enrolled in Original Medicare. Doing so outside the open enrollment window allows insurance companies to underwrite your application.

Insurance companies review your medical history during underwriting. They can deny you coverage or charge you higher rates based on their findings.

You can receive guaranteed Medigap coverage at the lowest premium during one of two open enrollment periods:

Medigap Open Enrollment Period (MOEP). The MOEP is a six-month period that starts the month you‘re both 65 and enrolled in Medicare Part B. It applies to you if you don’t have health insurance coverage other than Medicare.

Special Enrollment Period (SEP). You can delay enrolling in Medicare if you receive insurance from a company with more than 20 employees. Medicare gives you an eight-month period to sign up for Part B after your employer coverage ends. Once your Part B enrollment begins, you have six months to enroll in a Medigap plan.

Research your options to see which plan type best fits your needs and budget. You can review the differences between Plans A through N on Medicare.gov. You can also compare Medigap plans with an insurance broker or agent.

Medicare.gov shows which insurance companies offer Medigap plans in your area. You can view the premiums for each available option. 

After making a choice, you can apply for coverage through the insurance company, a broker, or an agent.

Changing Medigap plans may raise your premium. After enrolling in a plan during your initial MOEP, the plan automatically renews each year.

You lose this guaranteed protection if you change plans. Any new insurance company you apply to is allowed to underwrite your application. They can deny you coverage or charge you a higher premium.

Seniors with low incomes and adults with disabilities may qualify for a Medicare Savings Program. There are four different programs you can apply to through your state.

If approved, the programs help cover your Part A and Part B premiums, deductibles, coinsurance, and copayments. Some plans help pay for prescription medicines.

Income and resource limits to qualify change yearly and vary depending on the program. 2022 income limits for an individual range from $1,153 to $1,549 a month. The current limit for individuals with disabilities is $4,615 a month.

Medigap plans can save you money by paying many of Medicare's out-of-pocket costs. However, they're not required or always necessary.

You can only purchase a Medigap plan if you're enrolled in Original Medicare.

You don’t need a Medigap plan if you have Original Medicare and already have supplemental health insurance. Some people receive this through Medicaid or a former employer. 

You don’t need a Medigap plan if you have a Medicare Advantage plan from a commercial insurance company. These plans replace both Original Medicare and Medicare supplement plans.