Medigap Basics: What It Is and Who Can Buy It

Medicare can cover a lot, but it does not pay for everything. That’s where Medigap (also called Medicare Supplement Insurance) often comes in.

This guide explains in plain language what Medigap is, who can buy it, when you can sign up, and how to move forward through official Medicare channels. HowToGetAssistance.org is not a government site and does not process any applications. Instead, this article is meant to help you understand your options before you contact official offices or licensed professionals.

What Is Medigap?

Medigap is private health insurance that helps pay some of the “gaps” in Original Medicare (Medicare Part A and Part B). These gaps can include:

• Deductibles (what you pay before Medicare starts paying)
• Coinsurance (your share of the cost after Medicare pays its part)
• Copayments (fixed amounts you pay for certain services)
• In some plans, limited coverage for care outside the U.S.

Key points:

• Medigap policies are offered by private insurance companies, not Medicare itself.
• Medigap works only with Original Medicare (Part A and B), not with Medicare Advantage plans.
• Medigap policies are usually labeled as Plans A, B, C, D, F, G, K, L, M, and N (plan letters).
• Each plan letter must offer standardized benefits in most states. For example, a Plan G from one company must cover the same basic benefits as a Plan G from another company, though premiums can differ.

A Medigap policy is meant to help reduce your out-of-pocket costs when you use Medicare-covered services. It does not replace Medicare; it adds to it.

What Does Medigap Typically Cover (and Not Cover)?

Medigap policies are designed to cover certain costs that Original Medicare leaves for you to pay. They usually help with:

• Part A coinsurance and hospital costs
• Part B coinsurance or copayments
• Blood (first 3 pints) in many plan types
• Hospice care coinsurance or copayments
• Skilled nursing facility coinsurance (in many plans)
• Part A deductible (in many plans)
• Part B deductible (only in older Plans C and F for people who were eligible for Medicare before 2020)
• Limited foreign travel emergency care (in certain plans)

Medigap does not typically cover:

• Prescription drugs (you generally need a separate Medicare Part D plan for that)
• Long‑term care (like most nursing home care or assisted living)
• Vision or dental routine services
• Hearing aids
• Private-duty nursing
• Non-Medicare covered services (if Medicare doesn’t approve it, Medigap usually doesn’t pay either)

Because each plan type is different, many people compare coverage using the standard Medigap plan chart provided on the official Medicare website or by a licensed insurance agent.

Who Can Buy a Medigap Policy?

To buy Medigap, you usually must:

1. Be enrolled in Original Medicare Part A and Part B, and
2. Live in the plan’s service area (usually the state where the plan is offered).

You generally cannot buy a Medigap policy if you only have:

• Medicare Advantage (Part C) without returning to Original Medicare
• Medicaid only (though some people have Medicare and Medicaid together—those cases are more complex and often need personalized guidance)

Typical eligibility situations

You may be able to buy a Medigap plan if:

• You are 65 or older and have both Part A and Part B.
• You are under 65 with Medicare due to a disability or End-Stage Renal Disease (ESRD) and live in a state where Medigap plans are sold to people under 65.
  • Rules for people under 65 vary widely by state. Some states require companies to offer at least one Medigap plan to people under 65; others do not.

Because Medigap is sold by private insurers, each company can decide which plans to offer in each state, as long as they follow federal and state rules.

Key Enrollment Windows: When Are You Protected?

The best time for most people to buy a Medigap policy is during their Medigap Open Enrollment Period. In some other situations, you may have “guaranteed issue rights.” These rights affect whether you can be turned down or charged more because of your health.

Medigap Open Enrollment Period (OEP)

Your Medigap Open Enrollment Period is a 6-month window that:

• Starts the first month you are BOTH:
  • 65 or older, and
  • Enrolled in Medicare Part B, and
• You’re enrolled in Original Medicare, not a Medicare Advantage plan.

During this 6-month window:

• You can buy any Medigap policy sold in your state.
• Insurance companies cannot:
  • Deny you coverage because of health problems.
  • Charge you more because of your health history.
  • Make you wait for coverage to start, except in limited cases related to preexisting conditions.

If you miss this window, you may still be able to buy Medigap, but:

• You might be denied based on your health.
• You might pay more because of medical underwriting (health questions and history review).

Guaranteed Issue Rights (Protection in Certain Situations)

In some circumstances, you have “guaranteed issue rights” (sometimes called “Medigap protections”). With these rights:

• Companies must sell you certain Medigap policies,
• Must cover your preexisting conditions, and
• Cannot charge you more because of past or current health problems.

Common situations where guaranteed issue rights may apply include:

• Your Medicare Advantage plan stops offering coverage in your area or leaves Medicare.
• You move out of your Medicare Advantage plan’s service area.
• You had Original Medicare and a group health plan (such as from an employer) and that plan is ending.
• You try a Medicare Advantage plan for the first time and decide to switch back to Original Medicare within a certain trial period (often 12 months).

The exact rights and timelines depend on federal and state rules, so it’s important to check with:

• The official Medicare helpline, or
• Your State Health Insurance Assistance Program (SHIP), or
• A licensed insurance agent familiar with your state’s rules.

Who Usually Cannot Buy Medigap (or Faces Limits)?

You may be restricted or face higher costs if:

• You are under 65 on Medicare due to disability and your state does not require insurers to sell Medigap policies to people under 65.
• You want Medigap while enrolled in a Medicare Advantage plan (you usually cannot have both at the same time).
• You missed your Medigap Open Enrollment Period and do not have a guaranteed issue right.
• You are relying only on Medicaid for medical coverage (Medicaid rules work differently; some people with both Medicare and Medicaid may not need Medigap at all).

If you are in one of these situations, it may help to contact your:

• State Health Insurance Assistance Program (SHIP), or
• State department of insurance,
  to understand what’s allowed in your state.

How Medigap Plans Compare: A Simple Overview

Here is a simplified comparison of common Medigap plan features. This is only a general guide; for full details you would need the official Medigap plan chart or materials from a licensed agent or insurer.

This table is meant to help you frame your questions when you speak with official Medicare contacts or licensed agents.

Typical Costs of Medigap Policies

Medigap policies have monthly premiums in addition to:

• Your Medicare Part B premium, and
• Any premiums for other coverage, such as Part D.

Premiums can vary based on:

• The plan type (A, G, N, etc.)
• The insurance company
• Your age (some states use “attained-age,” “issue-age,” or “community-rated” pricing)
• Where you live
• Whether you smoke, in some cases

Even though coverage is standardized by plan letter in most states, prices can be very different from one company to another. Many people:

• Request quotes from several insurers, and
• Ask about how premiums may increase over time.

Basic Steps to Explore and Buy a Medigap Plan

You cannot buy Medigap through HowToGetAssistance.org, but you can use this checklist to prepare before you contact official resources or licensed professionals.

1. Confirm Your Medicare Status

Make sure you:

• Are enrolled in Medicare Part A and Part B.
• Know whether you have Original Medicare or a Medicare Advantage plan.

You can check this by:

• Reviewing your Medicare card (red, white, and blue card).
• Contacting Medicare’s official helpline.
• Accessing your information through the official Medicare online portal, if you have an account.

2. Check Your Enrollment Window

Identify whether you are:

• In your 6‑month Medigap Open Enrollment Period, or
• In a situation that may give you guaranteed issue rights, or
• Applying outside these protected times (where medical underwriting may apply).

If you’re not sure, you can:

• Call the official Medicare number, or
• Reach out to your State Health Insurance Assistance Program (SHIP) for free, unbiased counseling.

3. List Your Coverage Priorities

Before you talk to an agent or company, think about:

• How often you see doctors or specialists.
• Whether you travel outside the U.S. and want limited foreign travel emergency coverage.
• Whether you can manage higher premiums for potentially lower out-of-pocket costs, or vice versa.

Having these priorities ready can make your conversation with a licensed agent or counselor more productive.

4. Compare Medigap Plan Types Available in Your Area

You can compare:

• Plan letters (A, G, N, etc.) and what they cover.
• Monthly premium ranges from different companies.
• Whether the company has any household discounts (some do, if multiple people in the same home enroll).

Most people do this by:

• Contacting insurers directly,
• Speaking with a licensed insurance agent who works with multiple companies, or
• Reviewing information on the official Medicare site and from their state’s department of insurance.

5. Apply Through an Official Channel

Once you decide on a plan and insurer, you usually:

• Complete an application (online, by phone, or on paper) with the insurance company or licensed agent.
• Provide details about:
  • Your Medicare coverage
  • Your address and contact information
  • Your start date for Part B
  • Your desired effective date for the Medigap policy
• If you are outside a protected enrollment period, you may be asked health questions.

The exact process and available methods (online, phone, or in-person) depend on:

• The insurance company, and
• Your state’s rules.

Documents and Information You May Need

Each insurer’s application is a bit different, but you will usually need:

• Your Medicare card
  • To provide your Medicare Number
  • To confirm your Part A and Part B effective dates
• Photo ID (such as a driver’s license or state ID)
• Address and contact information
• Payment information for premiums (such as bank account or billing address)
• If applicable, information about:
  • Your current Medicare Advantage plan (if you’re leaving it)
  • Your group or employer coverage (if it’s ending)
  • Any relevant COBRA or retiree plans

To avoid delays, make sure your name, date of birth, and Medicare number are written accurately and match official records.

What Happens After You Apply?

After you submit an application through the insurer or agent:

1. Application review

   • If you are within your Medigap Open Enrollment Period or have a guaranteed issue right, the company generally must accept you.
   • If you apply outside these protections, the company may:
     • Approve coverage as requested
     • Offer coverage with conditions (such as a start date after a waiting period for preexisting conditions, where allowed)
     • Deny the application

2. Decision notice

   • The insurer usually sends you a written notice or packet with:
     • Approval or denial
     • Policy details
     • Effective date (when coverage starts)
     • Information on premiums and billing

3. Coordination with other coverage

   • If you are leaving a Medicare Advantage plan, you generally must:
     • Return to Original Medicare, and
     • Avoid overlapping coverage dates if possible.
   • If you have employer or union coverage, check with that plan before buying Medigap, as Medigap could affect those benefits.

If something is unclear, you can contact:

• The insurance company
• Your agent, if you used one
• Your SHIP counselor for neutral guidance

Common Reasons for Delays or Denials

People sometimes run into problems when applying for Medigap. Common issues include:

• Applying after the Open Enrollment Period without guaranteed rights, leading to:
  • Medical underwriting
  • Possible denial due to health history
• Incomplete or incorrect applications, such as:
  • Missing Medicare Number
  • Wrong effective dates for Part A or B
  • Missing signatures
• Confusion about coverage type, such as:
  • Applying for Medigap while still enrolled in a Medicare Advantage plan
  • Not properly ending an old Medigap policy when switching to a new one
• State-specific restrictions, especially for:
  • People under 65
  • Certain plan letters that are not sold in a specific state

If you are denied or delayed:

• You can ask the insurer for the reason in writing.
• You can consult your State Health Insurance Assistance Program (SHIP) or state department of insurance to understand your options.

What If You’re Denied or Don’t Qualify for Medigap?

If you cannot get a Medigap policy or it is too costly, you still may have options:

• Medicare Advantage (Part C)

  • Offers an alternative way to receive Medicare benefits through private plans.
  • Often includes doctor and hospital coverage, sometimes prescription drugs, and sometimes extra benefits.
  • Plans and costs vary by county and state, and there are specific enrollment periods.

• Stay with Original Medicare alone

  • You can use Original Medicare without Medigap, but you will be responsible for more out-of-pocket costs.
  • Some people combine this with Part D and, where available, Medicaid or local assistance programs.

• Medicaid (for low-income individuals)

  • If your income and assets are low enough, you might qualify for Medicaid in your state.
  • People who have both Medicare and Medicaid may have many costs covered and often don’t need Medigap.

• Medicare Savings Programs

  • State-run programs that may help pay your Medicare premiums and sometimes your deductibles and coinsurance, if you meet income and resource limits.

For any of these, you would generally contact:

• Your state Medicaid office
• Your state benefits or human services agency
• The official Medicare helpline
• Your local Area Agency on Aging or 211 for referrals to counseling services

Appeals and Complaints: What If Something Seems Wrong?

If you believe:

• Your Medigap application was processed incorrectly, or
• Your rights were not honored, especially when you believe you had a guaranteed issue right,

you can:

1. Ask the insurance company for an explanation in writing.
2. Contact your State Health Insurance Assistance Program (SHIP) for help understanding your rights.
3. File a complaint with your state department of insurance, which regulates insurance companies in your state.

Appeal procedures and complaint processes vary by state, but they usually:

• Allow you to submit your concern in writing or by phone.
• Require the insurer to respond within certain time frames.
• Provide a way to escalate issues if they are not resolved.

How to Verify You’re Using an Official Channel (Avoiding Scams)

Because Medigap is sold by private companies, it’s important to confirm you are dealing with legitimate, licensed entities and not scams.

Here are practical tips:

• Check for official government contacts.
  • Use phone numbers and websites published by Medicare, your state insurance department, or your SHIP.
• Verify the agent or company.
  • Ask for the agent’s full name, company, and state license number.
  • Confirm this information with your state department of insurance.
• Be cautious of pressure tactics.
  • Be wary if someone:
    • Insists you must sign up “today only”
    • Will not let you review written materials
    • Asks for cash or payment through unusual methods
• Protect your Medicare Number.
  • Share your Medicare Number only when you are sure you are speaking with a trusted, legitimate insurer, agent, or official program representative.
• Look for clear written information.
  • You should receive clear written details about:
    • The Medigap plan type
    • Premiums
    • What is and is not covered
    • Cancellation and change rules

If something doesn’t feel right, you can pause and:

• Call the official Medicare helpline to ask about the plan or situation.
• Contact your SHIP or state insurance department to confirm whether the agent or company is legitimate.

Understanding Medigap—what it covers, who can buy it, and when you’re protected—can help you make more confident decisions when you contact official Medicare channels or licensed professionals. Use this information as a starting point, then reach out to Medicare, your SHIP, your state insurance department, or a licensed agent to review the choices and rules that apply where you live.