Medigap Policies Explained: How They Work and Whether They’re Right for You

If you’re enrolled in Original Medicare (Parts A and B), you’ve probably noticed that it doesn’t cover everything. That’s where a Medigap policy can come in.

This guide walks you through, in plain language, what a Medigap policy is, how it works with Medicare, who can get it, and what to think about before you enroll.

What Is a Medigap Policy?

A Medigap policy (also called Medicare Supplement Insurance) is a private health insurance plan that helps pay some of the out-of-pocket costs that Original Medicare doesn’t cover.

Original Medicare generally includes:

Part A – hospital insurance
Part B – medical insurance

Medicare pays its share of covered services. A Medigap policy is designed to help cover your share, such as:

Deductibles (the amount you pay before Medicare starts paying)
Coinsurance (the percentage you pay after Medicare pays its part)
Copayments (set dollar amounts for certain services)

Think of Medigap as a “helper policy” that fills in some of the “gaps” in Original Medicare’s coverage.

How Medigap Works With Original Medicare

Medigap does not replace Medicare. Instead, it works alongside Original Medicare:

You keep Medicare Parts A and B
You pay your Part B premium (and Part A if applicable)
You also pay a monthly premium for your Medigap policy
When you get care:
- Medicare pays its share of the approved amount
- Your Medigap policy may pay all or part of the remaining amount, depending on the plan

You continue using your Medicare card and your Medigap card when getting services. Most people find the process seamless because providers bill Medicare first, then the Medigap insurer is billed automatically in the background.

What Medigap Policies Generally Cover

Every Medigap policy is standardized by lettered plan types (such as Plan A, B, D, G, K, L, M, N). While benefits vary by plan type, Medigap policies commonly help with:

Medicare Part A coinsurance and hospital costs
Part B coinsurance or copayments
Blood (first 3 pints) for medical procedures
Part A hospice care coinsurance or copayments
Skilled nursing facility coinsurance (for certain plans)
Part A deductible (for certain plans)
Part B deductible (only certain older plans still offer this, and new enrollees generally can’t get it)
Foreign travel emergency coverage (for some plans, up to certain limits)

What Medigap Does Not Cover

Medigap policies are not all-purpose health plans. They do not typically cover:

Prescription drugs (you usually need a separate Medicare Part D plan)
Routine dental, vision, or hearing services
Long-term care (such as most nursing home or custodial care)
Private-duty nursing
Non-Medicare-covered services

If Medicare does not cover a service at all, most Medigap policies will not pay for it either.

Medigap vs. Medicare Advantage: Important Distinction

People often confuse Medigap with Medicare Advantage, but they are very different:

Feature	Medigap Policy	Medicare Advantage Plan
Works with…	Original Medicare (Parts A & B)	Replaces Original Medicare
Enrollment	You keep Parts A & B	You enroll in a private Part C plan
Provider access	Typically any provider that takes Medicare	Often uses networks (HMO, PPO, etc.)
Prescription drug coverage	Usually not included	Often included
Role	Helps with costs Medicare doesn’t pay	Bundles Medicare benefits in one plan
Have both at once?	No – not allowed	No Medigap with Medicare Advantage

If you choose Medicare Advantage, you generally cannot use a Medigap policy. Medigap is for those who decide to stay with Original Medicare.

Who Is Eligible for a Medigap Policy?

You are generally eligible to apply for a Medigap policy if:

You are enrolled in Medicare Part A and Part B, and
You live in the policy’s service area

However, whether an insurance company must sell you a policy and what it can charge often depends on timing and certain rights you may have.

The Medigap Open Enrollment Period: Your Key Window

For many people, the best time to buy a Medigap policy is during your Medigap Open Enrollment Period.

This period:

Starts the first month you are both 65 or older and enrolled in Part B
Lasts for 6 months

During this 6‑month window:

You have a “guaranteed issue right” to buy any Medigap policy sold in your state (in most cases)
The insurance company cannot:
- Deny you coverage based on health
- Charge you more because of past or present health problems
- Make you wait for coverage of preexisting conditions longer than allowed rules

If you apply after this window, you can usually still apply for Medigap, but:

The company may use medical underwriting (health questions)
You may be denied coverage or charged a higher premium, depending on your health

Some people younger than 65 who qualify for Medicare due to disability or certain conditions may have different Medigap rights depending on their state.

Guaranteed Issue Rights (When You’re Protected Outside Open Enrollment)

In certain situations, you may have guaranteed issue rights to buy a Medigap policy, even outside your initial 6‑month open enrollment. Common examples include:

Your Medicare Advantage plan leaves your area or stops participating in Medicare
You move out of your Medicare Advantage plan’s service area
You lose certain other types of coverage that worked with Medicare through no fault of your own

When you have these rights:

Companies generally must sell you certain Medigap policies
They cannot charge you more due to health issues
They cannot impose certain waiting periods

These protections are specific and time-limited, so many people keep documentation and pay attention to deadlines when coverage changes.

Types of Medigap Plans (Standardized Options)

Medigap policies are standardized into plan types identified by letters (for example, Plan A, Plan G, Plan N). In most states:

Each lettered plan offers the same core benefits, no matter which company sells it
The only differences between companies for the same plan letter are usually:
- Monthly premium
- Customer service practices
- Additional administrative features (not core benefits)

Some plan letters are more common and widely chosen, such as Plan G and Plan N for newer enrollees, but the “right” plan depends on your budget, health needs, and preferences for predictable costs versus paying more as you go.

How Medigap Premiums Are Priced

Medigap policies charge a monthly premium, in addition to your Medicare Part B premium. Insurers typically use one of three common pricing methods:

Community-rated (no age-rated)
- Everyone pays the same premium, regardless of age (in a given area)
- Premiums may increase over time due to inflation or other factors, but not because you age
Issue-age-rated
- Premium is based on the age you are when you first buy the policy
- Younger buyers usually pay less, and the premium does not increase due to aging, though it can still rise for other reasons
Attained-age-rated
- Premium is based on your current age, and it typically increases as you get older
- Often starts lower at younger ages, but can become more expensive over time

Understanding how the premium is set can help you anticipate future costs, not just the price today.

What to Consider Before Buying a Medigap Policy

When deciding whether a Medigap policy is right for you, it can be helpful to think through several angles:

1. Your Overall Health and Usage

Do you see doctors frequently or expect ongoing outpatient care?
Are you comfortable with copayments and coinsurance, or would you rather pay a higher monthly premium for more predictable costs?

Medigap can be appealing to people who want to limit surprise bills and prefer more predictable coverage.

2. Your Budget

Factor in:
- Monthly Part B premium
- Monthly Medigap premium
- Potential Part D premium (for prescription drugs)
Ask yourself:
- Can you comfortably afford the monthly costs?
- Would you rather pay less per month and more when you use services, or the reverse?

3. Provider Flexibility

With Original Medicare and Medigap:

You can generally see any doctor or specialist who accepts Medicare, often without referrals
This can be helpful if you travel or divide your time between different locations

If you prefer broad provider choice and less reliance on networks, this structure may appeal to you.

4. Travel Habits

Certain Medigap plans include limited foreign travel emergency coverage
Original Medicare alone typically has very limited coverage outside the U.S.

If you often travel internationally, the specific Medigap benefit details can matter.

5. Long-Term Planning

It can be easier to get comprehensive Medigap coverage when you first become eligible. If you delay and later develop health problems:

You might face higher premiums or have fewer options in some situations
Some people choose a Medigap plan early to help avoid underwriting issues later

Practical Tips for Evaluating Medigap Options

Here are some structured questions and tips people commonly use when comparing Medigap policies:

Start with your needs
- How often do you visit doctors or specialists?
- Are you comfortable with some ongoing out-of-pocket exposure?
Compare plan letters, not just companies
- First decide which plan letter matches your coverage needs
- Then compare premiums and features from multiple insurers for the same plan letter
Ask how premium increases work
- Is the policy community-rated, issue-age-rated, or attained-age-rated?
- How often have premiums changed historically (if the agent can provide that context)?
Check what’s included and excluded
- Which Medicare gaps does the plan cover fully?
- Which does it cover partially or not at all?
Confirm you can’t use Medigap with Medicare Advantage
- If you ever switch to a Medicare Advantage plan, you generally cannot keep or use your Medigap policy
- Plan accordingly if you think you might switch in the future

Simple Snapshot: Medigap in One Glance

Medigap Policy Basics

What it is:
A private insurance policy that works with Original Medicare to help pay out-of-pocket costs like deductibles, copayments, and coinsurance.
Who it’s for:
People with Medicare Parts A and B who want more predictable costs and the flexibility to see providers who accept Medicare.
What it covers:
Some or all of certain Medicare cost gaps, depending on the plan letter you choose.
What it doesn’t cover:
Most dental, vision, hearing, long-term care, and generally prescription drugs (you usually need a separate Part D plan).
Key timing:
Your 6‑month Medigap Open Enrollment Period, starting when you’re 65+ and enrolled in Part B, is usually the easiest time to get a policy.

Is a Medigap Policy Right for You?

A Medigap policy can be a strong fit if you:

Plan to stay with Original Medicare
Want broad provider choice
Prefer to limit unexpected medical bills for covered services
Can manage an additional monthly premium for the peace of mind it offers

On the other hand, if you are comfortable using a Medicare Advantage plan with networks and different cost structures, or if you rarely use medical services and want to keep monthly costs as low as possible, you may decide Medigap is not necessary for you.

Understanding what a Medigap policy is—a standardized supplemental insurance option that helps pay your share of Medicare-covered costs—can make it much easier to compare it with other Medicare choices and decide which arrangement best supports your health care needs and budget.