Medicare Supplement (Medigap), explained

What Medigap is

Original Medicare (Part A and Part B) pays a large share of hospital and medical bills, but not all of them. In 2026 you still owe a Part A hospital deductible of $1,736 per benefit period, a Part B deductible of $283 for the year, and usually 20% of many doctor and outpatient bills. There is no yearly cap on that 20% unless you have other coverage.

A Medicare Supplement Insurance policy — also called Medigap — is sold by a private company. It helps pay some or all of those leftover costs. You pay a monthly premium to the company, on top of your Part B premium.

• You must have Part A and Part B to buy a Medigap policy.
• You cannot use Medigap with Medicare Advantage. If you join an Advantage plan, you should not keep paying for Medigap to cover Advantage copays. It will not.
• Medigap does not include Part D drugs for policies sold after 2005. If you want drug coverage with Original Medicare, you join a separate Part D plan.
• Routine dental, glasses, and hearing aids are generally not covered by Original Medicare or by standard Medigap.

How the letters work

In most states, Medigap policies are standardized and named by letter: A, B, C, D, F, G, K, L, M, and N. A Plan G from one company covers the same basic benefits as a Plan G from another company. What you compare is the premium, the company’s service, and any extra rules such as Medicare SELECT (which may require certain hospitals).

Massachusetts, Minnesota, and Wisconsin use different standardized plans. If you live in one of those states, ask us or your state insurance department for the local chart.

When you can buy a policy

Your best window is the six-month Medigap Open Enrollment Period. It starts the first month you are 65 or older and enrolled in Part B. During that window, you can buy any Medigap policy sold in your state, even if you have health problems. Companies cannot use medical underwriting to turn you down or charge you more because of health.

After that window, a company may ask about your health and can decline you, unless you have a guaranteed-issue right. Common examples include leaving certain employer coverage, or limited “trial” rights if you try Medicare Advantage when you first get Medicare and then return to Original Medicare. State rules can add extra rights. Ask before you drop a plan.

Standardized Medigap policies are guaranteed renewable. The company cannot cancel you just because you get sick, as long as you pay the premium.

Good to know before you enroll

You still pay Medicare

Medigap does not replace Part A or Part B. You keep paying the Part B premium, usually taken from your Social Security check.

Premiums are not the same everywhere

The same letter can cost more or less depending on your age, tobacco use, ZIP code, and how the company sets rates (issue age, attained age, or community rated). Compare more than one company.

High-deductible Plan G (and F, if you qualify)

In some states you can buy a high-deductible version. You pay Medicare-covered costs up to $2,950 in 2026 before the Medigap policy pays. The monthly premium is usually lower.

Household discounts

Some companies offer a discount if more than one person in the home has a policy with them. That is a company rule, not a Medicare rule.

Doctors who take Medicare

With Original Medicare plus Medigap, you generally do not have a network. Confirm the office accepts Medicare. If a doctor does not accept assignment, Plan G or Plan F can help with excess charges.

Travel in the U.S.

Original Medicare and Medigap work nationwide with providers that accept Medicare. That is one reason snowbirds often look at Medigap instead of a local Advantage network.

A licensed agent at Prime Integrity Insurance can help you compare lettered plans sold where you live. We do not offer every plan in your area. You can also use the official Medigap finder at Medicare.gov, or call us at (877) 273-0393.

Next: Medicare Advantage (Part C) or Part D drug plans.