Medicare Supplement

Why Medigap letters mean identical benefits in Carbondale

CARBONDALE, Ill. — If you have Original Medicare (Part A and Part B), you already know it covers a big share of your hospital and doctor bills. But it doesn't pay for everything. You're still on the hook for deductibles, coinsurance, and copays — and Original Medicare has no yearly limit on what you might owe out of pocket.

What Medigap actually does

That's the gap Medicare Supplement Insurance, better known as Medigap, is designed to fill. Medigap is sold by private insurance companies, but the benefits inside each plan are set by the federal government. You pay a monthly premium to the insurance company, and in return, the plan helps cover some of the costs Original Medicare leaves behind.

Medigap works only with Original Medicare. It does not work with Medicare Advantage plans.

Why the plans have letters

Here's where it gets easier than it sounds. In most states, Medigap plans are standardized and labeled with letters — Plan A, B, C, D, F, G, K, L, M, and N.

The letter tells you what the plan covers. So Plan G from one insurance company must cover the exact same benefits as Plan G from any other insurance company. The only real differences between two Plan G policies are the price, the customer service, and any small extras the carrier may throw in.

That means shopping for Medigap is mostly a matter of two questions: 1. Which letter fits the level of coverage I want? 2. Which company offers that letter at a price and service level I like?

Massachusetts, Minnesota, and Wisconsin standardize their plans a little differently, but Illinois follows the standard letter system.

What each letter generally covers

Every standardized Medigap plan covers at least a core set of benefits, including Part A hospital coinsurance and an extra 365 days of hospital coverage after Medicare benefits are used up. From there, the letters branch out.

• Plans A and B cover the basics.
• Plans K, L, and M share costs with you at different percentages, which usually means lower premiums but more of your own money when you use care.
• Plan N covers a lot but asks you to pay small copays for some office and emergency room visits.
• Plans G and F are the most comprehensive. Plan F is only available to people who were eligible for Medicare before January 1, 2020. If you became eligible on or after that date, Plan G is generally the most comprehensive plan you can buy.
• High-deductible versions of Plan G and Plan F exist for people who want a lower premium in exchange for paying a set amount before benefits kick in.

For a full side-by-side chart of what each letter covers, Medicare.gov keeps an up-to-date grid at medicare.gov/health-drug-plans/medigap.

When you can buy Medigap matters — a lot

The single most important thing to know about Medigap is timing.

You have a 6-month Medigap Open Enrollment Period that starts the month you're 65 and enrolled in Part B. During that window, insurance companies must sell you any Medigap plan they offer at their best available rate, regardless of your health history. This is called guaranteed issue.

After that window closes, in most cases insurance companies in Illinois can use medical underwriting. That means they can look at your health, charge you more, or turn you down. There are limited exceptions — for example, if certain other coverage ends — but the safest move is to make your Medigap decision during that first 6-month window.

A Carbondale snapshot

Carbondale sits in Jackson County, where residents have access to Medigap plans from multiple private insurance companies licensed to sell in Illinois. Because the benefits inside each letter are standardized by federal rule, a Plan G sold in Jackson County covers the same services as a Plan G sold anywhere else in Illinois — but premiums can vary from one company to the next, so it pays to compare.

You can look up plans available in your ZIP code using the plan finder at medicare.gov, or call your local Illinois SHIP counselor for free, unbiased help. SHIP does not sell insurance.

Medigap vs. Medicare Advantage — not the same thing

This trips a lot of people up, so it's worth saying plainly: Medigap and Medicare Advantage are two different roads.

• Medigap works alongside Original Medicare and helps pay your share of costs. It does not include prescription drug coverage — you'd add a separate Part D plan.
• Medicare Advantage (Part C) replaces Original Medicare as your delivery system. It bundles hospital, medical, and often drug coverage together, and often uses provider networks.

You can't have both at the same time. Choosing between them is a personal decision that depends on your doctors, your medications, your budget, and how you like to use health care.

Quick FAQ

Do all Medigap plans cover prescription drugs? No. Medigap plans sold today do not include prescription drug coverage. If you want drug coverage with Original Medicare and Medigap, you'll add a stand-alone Part D plan. In 2026, Part D has an annual out-of-pocket cap of $2,100 and a maximum deductible of $615.

Can I switch from one Medigap plan to another later? You can apply anytime, but outside of your initial 6-month window or a special guaranteed-issue situation, the insurance company can review your health and decide whether to accept you and at what price. Talk to a SHIP counselor before you drop a plan.

Is Plan F really going away? Plan F is not being canceled for people who already have it or who were eligible for Medicare before January 1, 2020. But if you became eligible on or after that date, you can't buy Plan F. Plan G is the closest comparable option for newer enrollees.

Does Medigap cover care if I travel outside Illinois? Yes. Because Medigap works with Original Medicare, and Original Medicare is accepted by most providers across the country, your Medigap plan travels with you. Some plans also include limited foreign travel emergency coverage.

Where to get help you can trust

Medigap decisions are personal, and the best answers come from official, unbiased sources — not a sales call.

• Medicare.gov — Compare plans available in your ZIP code and see the standardized benefits chart.
• 1-800-MEDICARE (1-800-633-4227) — Available 24/7.
• Illinois SHIP (Senior Health Insurance Program) — Free, one-on-one counseling from trained volunteers. You can find your local office through the Illinois Department on Aging.

Take your time, ask questions, and remember that with Medigap, the letter tells you the coverage — the company you buy it from is a separate choice.