Last updated: October 18, 2026

Medicare Supplement Insurance (Medigap)

Help Cover the Costs Original Medicare Doesn't Pay

Original Medicare (Parts A and B) helps pay for many hospital and medical expenses, but it doesn't cover everything. Deductibles, coinsurance, and copayments can leave you responsible for significant out-of-pocket costs.

Medicare Supplement Insurance, also called Medigap, helps fill those coverage gaps. These policies are offered by private insurance companies and work alongside Original Medicare to help make healthcare expenses more predictable.

What Does Medicare Supplement Insurance Cover?

Depending on the plan you choose, Medicare Supplement Insurance can help pay for:

Part A hospital costs: Coinsurance and additional hospital expenses after Medicare benefits are exhausted, subject to plan limits.
Part B coinsurance and copayments: Your share of the cost for Medicare-covered doctor visits, outpatient care, and medical services.
Medicare deductibles: Certain plans help pay the Part A hospital deductible. Some older plans also cover the Part B deductible.
Skilled nursing facility coinsurance: Additional costs for qualifying skilled nursing facility care.
Emergency medical care while traveling abroad: Certain plans provide limited foreign travel emergency benefits.
Part B excess charges: Plans F and G cover allowable excess charges when a provider doesn't accept Medicare assignment.

Not every Medicare Supplement plan covers every expense. The benefits you receive depend on the standardized plan you select.

How Does Medicare Supplement Insurance Work?

Medicare Supplement Insurance works with Original Medicare, rather than replacing it.

When you receive a Medicare-covered healthcare service:

Original Medicare pays first, according to Medicare's coverage and payment rules.
Your Medicare Supplement policy pays its share, depending on the benefits of your plan.
You pay any remaining costs that Medicare and your Supplement policy do not cover.

Freedom to Choose Your Healthcare Providers

One of the advantages of Original Medicare with a Supplement policy is flexibility.

You can generally visit any doctor, specialist, or hospital in the United States that accepts Medicare. You typically don't need to stay within a plan's provider network or obtain referrals to see specialists.

This can be especially valuable if you travel frequently, spend part of the year in another state, or prefer to maintain flexibility when selecting healthcare providers.

Understanding Medicare Supplement Plans

Medicare Supplement plans are standardized and identified by letters, including Plans A, B, D, G, K, L, M, and N. Plans C and F remain available to certain people who were eligible for Medicare before January 1, 2020.

A Plan G from one insurance company offers the same standardized basic benefits as a Plan G from another company. However, premiums, customer service, and pricing methods can differ.

Massachusetts, Minnesota, and Wisconsin have different standardized plan structures.

Medicare Supplement Plan G

Plan G provides broad coverage for many of the out-of-pocket expenses associated with Original Medicare.

It generally covers:

Medicare Part A deductible and coinsurance
Medicare Part B coinsurance and copayments
Skilled nursing facility coinsurance
Part B excess charges
Limited foreign travel emergency benefits

What you pay: Plan G does not cover the annual Medicare Part B deductible. You are responsible for that deductible, your monthly premiums, and expenses outside the policy's coverage.

For people newly eligible for Medicare beginning January 1, 2020, Plan G provides some of the most comprehensive standardized Medigap benefits available.

Medicare Supplement Plan N

Plan N is another option for people looking to balance monthly premiums with out-of-pocket expenses.

Like Plan G, Plan N covers many expenses that Original Medicare leaves behind. However, there are important differences:

You pay the annual Medicare Part B deductible.
You may pay up to $20 for certain office visits.
You may pay up to $50 for certain emergency room visits that do not result in an inpatient admission.
Plan N does not cover Part B excess charges.

Plan N may have a lower monthly premium than Plan G, depending on the insurance company and your circumstances.

What About Plan F?

Plan F offers extensive benefits, including coverage of the Medicare Part B deductible.

However, Plans F and C are not available to people who became newly eligible for Medicare on or after January 1, 2020.

If you were eligible for Medicare before that date, you may still qualify to purchase one of these plans, even if you have not previously enrolled.

People who already have these plans can generally keep their existing coverage as long as the policy remains in force.

Compare Medicare Supplement Plan Benefits

Because Medicare Supplement plans are standardized, comparing their benefits is an important first step.

Some plans offer broader coverage with potentially higher premiums. Others may have lower premiums but require you to pay more when receiving medical care.

Before choosing a plan, consider:

Your monthly premium
Your expected healthcare needs
Deductibles and copayments
Whether the plan covers Part B excess charges
The insurance company's pricing method and history of premium increases
Your eligibility and enrollment rights

Official Medicare Supplement benefits comparison:
Compare Medigap Plan Benefits at Medicare.gov

Important Medicare Supplement Limits for 2026 and 2027

Benefit	2026	2027
Plan K annual out-of-pocket limit	$8,000	$8,360
Plan L annual out-of-pocket limit	$4,000	$4,180
High-deductible Plans F and G	$2,950	$3,050

For Plans K and L, the policy pays 100% of covered services for the remainder of the calendar year after you meet the plan's annual out-of-pocket limit and the annual Medicare Part B deductible.

The high-deductible versions of Plans F and G require you to pay the applicable annual deductible for Medicare-covered expenses before those policies begin paying benefits.

These limits are established by the Centers for Medicare & Medicaid Services (CMS) and may change annually.

When Can You Enroll in Medicare Supplement Insurance?

Your Six-Month Medigap Open Enrollment Period

For most people, the best time to purchase Medicare Supplement Insurance is during their one-time, six-month Medigap Open Enrollment Period.

This period begins on the first day of the month when you are both:

Age 65 or older, and
Enrolled in Medicare Part B.

During this period, you can purchase any Medigap policy sold in your state, regardless of your health history. Insurance companies cannot deny you coverage or charge you more because of pre-existing health conditions.

If you delay enrollment in Part B because you are still working and have qualifying employer coverage, your Medigap Open Enrollment Period generally begins when your Part B coverage starts, provided you are at least 65.

What Happens if You Miss Your Enrollment Period?

You may still be able to apply for Medicare Supplement Insurance after your initial six-month period ends.

However, depending on your state and circumstances, insurance companies may use medical underwriting, charge higher premiums, or decline your application.

Certain situations provide additional protections known as guaranteed-issue rights.

These rights may apply when:

Your Medicare Advantage plan ends coverage or leaves your service area.
You move outside your Medicare Advantage plan's service area.
You lose certain qualifying employer or other health coverage.
You qualify for specific Medicare Advantage trial rights.
You qualify under additional state consumer-protection laws.

Guaranteed-issue rights have specific eligibility requirements, deadlines, and restrictions on which Medigap policies you can purchase.

Switching from Medicare Advantage to a Supplement

Medicare Advantage and Medicare Supplement Insurance are two different approaches to Medicare coverage.

If you have Medicare Advantage and want to return to Original Medicare with a Supplement policy, you need to coordinate your coverage carefully.

Federal law provides certain trial rights, including situations where you joined Medicare Advantage when first eligible for Medicare at age 65 and decide within the first year to switch to Original Medicare.

Other trial rights may apply if you previously dropped a Medigap policy to join Medicare Advantage for the first time.

Important: Simply deciding to leave Medicare Advantage does not automatically guarantee that you can purchase any Medigap policy without medical underwriting.

California Residents: The Medicare Supplement Birthday Rule

If you already have a Medicare Supplement policy in California, you may have a special opportunity to compare plans and potentially lower your premiums each year.

California's Medicare Supplement Birthday Rule generally allows eligible policyholders to switch to another Medicare Supplement policy offering equal or lesser benefits during a 60-day period beginning on their birthday.

During this period:

You may compare policies offered by different insurance companies.
You can apply for a plan with equal or lesser benefits.
Insurance companies cannot deny eligible applicants coverage or charge more based on their health history.
You may be able to lower your monthly premium while maintaining comparable coverage.

Why Review Your Coverage Every Year?

Even when two insurance companies offer the same standardized benefits, their premiums can differ. Rates can also change over time.

California's Birthday Rule provides an opportunity to compare your current coverage with other available policies without undergoing medical underwriting, provided you meet the rule's requirements.

California's Birthday Rule is a state-specific protection. Other states have different Medigap enrollment and switching rules.

Does Medicare Supplement Insurance Cover Prescription Drugs?

Medicare Supplement policies sold today do not include outpatient prescription drug coverage.

If you have Original Medicare with a Supplement plan and want prescription drug coverage, you can generally enroll in a separate Medicare Part D prescription drug plan.

Although Part D enrollment is optional, delaying enrollment without other creditable prescription drug coverage may result in a late enrollment penalty if you enroll later.

Medicare Supplement vs. Medicare Advantage: What's the Difference?

Both options can help manage healthcare costs, but they work differently.

Medicare Supplement (Medigap)	Medicare Advantage (Part C)
Works alongside Original Medicare	Provides Medicare Part A and Part B benefits through a private plan
Generally allows access to providers nationwide who accept Medicare	Often uses provider networks and service areas
Typically does not require specialist referrals	Some plans require referrals
Helps pay certain Original Medicare out-of-pocket costs	Has its own copayments, coinsurance, and annual medical out-of-pocket limit
Requires a separate Part D plan for drug coverage, if desired	Many plans include Part D drug coverage
Has a separate monthly policy premium	Premiums vary; some plans have a $0 additional plan premium

You must continue paying your Medicare Part B premium under either approach, unless another program or benefit pays it for you.

You generally cannot use a Medicare Supplement policy together with Medicare Advantage.

Neither option is automatically best for everyone. Your preferred providers, prescriptions, healthcare needs, budget, and eligibility should guide the decision.

Are Medicare Supplement Policies Guaranteed Renewable?

Yes. Standardized Medicare Supplement policies are generally guaranteed renewable.

This means that once you purchase a policy, you can normally keep it even if your health changes or you develop a serious medical condition.

Your insurance company generally cannot cancel your coverage because you become ill or begin using more healthcare services.

However, coverage may end under limited circumstances, including nonpayment of premiums, material misrepresentation on the application, or an insurer's bankruptcy or insolvency.

Guaranteed renewable does not mean your premium will remain the same. Insurance companies may increase premiums in accordance with applicable laws and policy terms.

Frequently Asked Questions About Medicare Supplements

Do I need Medicare Parts A and B to purchase a Supplement?

Generally, yes. Medicare Supplement Insurance is designed to work with Original Medicare, so you ordinarily need both Part A and Part B. Purchasing eligibility also depends on applicable enrollment and state rules.

Can I keep my doctor?

Generally, you can see any doctor or specialist in the United States who accepts Medicare, without having to stay within a Medigap provider network. You should always verify that your provider accepts Medicare before receiving care.

Do Medicare Supplement premiums increase?

Yes, premiums can change over time. Increases can depend on factors such as your insurance company's pricing method, age-related rating where permitted, healthcare costs, and approved rate adjustments.

Is Plan G better than Plan N?

Not necessarily. Plan G offers broader benefits, while Plan N may have lower premiums but requires additional copayments for some services and does not cover Part B excess charges. The best choice depends on your budget and healthcare preferences.

Can I change Medicare Supplement insurance companies?

Yes, but your ability to switch without medical underwriting depends on your enrollment rights and state law. California residents who already have Medigap coverage may qualify for additional protections under the Birthday Rule.

Does Medicare's October 15–December 7 Annual Enrollment Period apply to Medigap?

Not in the same way. The annual Medicare enrollment period primarily concerns Medicare Advantage and Part D coverage. Medigap has separate enrollment and switching rules, including your initial six-month Medigap Open Enrollment Period and applicable guaranteed-issue rights.