Medicare Supplement Plans

Medicare itself stays in place when you add a Medicare Supplement plan. Original Medicare remains your primary coverage, with the supplement sitting behind it. After you receive care, your provider sends the bill to Medicare first. Medicare covers its portion of the approved amount and passes the remainder to your Medigap carrier, which pays its portion according to your plan letter. Usually this all happens on its own, so you never have to submit a claim.

Since Medigap tracks Medicare, every provider nationwide that takes Medicare has to take your supplement too. That sets it apart from Medicare Advantage, which generally limits you to the plan’s network. It also explains Medigap’s appeal for travelers, people who split time between two states, and anyone who wants to visit specialists at major medical centers with no referrals.

To judge the value of a supplement, begin by looking at what Original Medicare leaves uncovered. A Medigap plan is designed to pay these costs:

Federal law sets exactly what each plan letter covers. A Plan G from one insurer covers precisely what a Plan G from any other insurer covers in your state, so once you pick a letter, the only things left to compare are price, how the insurer raises prices, discounts and service. See the 10 Medigap plans and the Medicare Supplement plans chart.

*Only people who became eligible for Medicare before January 1, 2020, can buy Plans C and F. **Plans K and L come with a yearly out-of-pocket limit that Medicare updates each year; once you hit it, the plan covers 100% of covered services for the remainder of the year. ***Plan N covers all Part B coinsurance apart from copays of up to $20 for certain office visits and up to $50 for ER visits that do not result in an inpatient admission. Massachusetts, Minnesota and Wisconsin use their own way of standardizing plans.

Most people new to Medicare choose one of three plans. They differ in how much you pay up front in premium versus how much you pay when you use care. See Plan G vs Plan N.

Plan G: the most complete plan for new enrollees

Plan G fills each gap in Original Medicare apart from the Part B deductible. After you satisfy that deductible every year, Medicare-approved care is typically paid in full, Part B excess charges included. Plan G became the top-selling plan in place of Plan F once Plan F stopped being available to new Medicare enrollees in 2020. See Medicare Plan G.

Plan N: pay small copays in return for a smaller premium

Plan N provides the same core coverage as Plan G apart from Part B excess charges, and it adds copays of up to $20 for certain office visits and up to $50 for emergency room visits that do not result in an inpatient admission. Its monthly cost is typically lower, so it may suit people who visit the doctor less frequently and live in areas where few doctors bill excess charges. See Medicare Plan N.

High-Deductible Plan G: the smallest premium, paired with an annual deductible

High-Deductible Plan G has the same benefits as Plan G, but you pay a yearly deductible before the plan pays. For 2027, that deductible is $3,050, up from $2,950 in 2026. Premiums are much lower, so it can suit healthy people who can afford the deductible in a bad year. See High-Deductible Plan G.

Medigap pays only toward services that Original Medicare covers. Since it adds no new benefit types, budget for the following on your own:

Most Medigap buyers pick up a Part D plan at the same time. The highest Part D deductible allowed for 2027 is $700, and out-of-pocket costs for covered drugs are capped at $2,400. Going without creditable drug coverage when you first become eligible may trigger a late enrollment penalty that lasts as long as you are on Part D. See Medicare Part D plans 2027.

In addition to your Part B premium, you pay the insurance company a monthly premium. Since benefits are the same for each letter, insurers compete on price, and one plan letter can be priced very differently by different companies within a single ZIP code.

How insurers price their policies

Which method applies depends on the insurer and the state. Before buying, find out how a policy is priced, not only what it costs now.

An attained-age policy with a cheap first-year rate may wind up costing you more over the years than one that began at a higher price. See how to compare Medicare Supplement plans.

This window happens once and does not repeat. If you delay Part B because you have coverage from a current employer, your Medigap Open Enrollment Period starts when you enroll in Part B. See the 6-month Medigap Open Enrollment Period.

Guaranteed issue rights

Under federal law, you also have the right to purchase certain Medigap plans with no health questions in particular circumstances, typically within 63 days of losing your other coverage. Typical examples include:

When you are under 65 and have Medicare due to a disability, insurers are not required by federal law to sell you Medigap, though many states require it. Pricing and available plans for those under 65 differ greatly from state to state.

You can have either a Medicare Supplement plan or a Medicare Advantage plan, not both. They take opposite approaches. See Medicare Advantage vs Medigap.

Medigap suits people who want the freedom to use any doctor along with predictable costs, and who can handle a higher premium. Medicare Advantage suits people who prefer a low premium plus extra benefits and do not mind a network. If your Medicare Advantage plan is ending and you are leaving it for 2027, you may have a guaranteed issue right to purchase Medigap.