Medicare Supplement

Medigap, explained: what those Plan A–N letters really mean

NORTH LAUDERDALE, Fla. — If you're new to Medicare, or helping a parent sort through the mail, you've probably run into a stack of brochures with letters like Plan G, Plan N, or Plan K. Those letters aren't marketing labels. They're a federal shorthand for Medicare Supplement Insurance, better known as Medigap, and they can make a real difference in how you handle out-of-pocket costs under Original Medicare.

Here's a plain-English look at what Medigap does, what it doesn't do, and how the standardized letters work.

What Medigap actually is

Medigap is private insurance that works alongside Original Medicare (Part A and Part B). After Medicare pays its share of a covered service, your Medigap policy picks up some or all of what's left — things like coinsurance, copayments, and in some cases the Part A hospital deductible.

Medigap does not replace Medicare. It sits on top of it. You keep your red, white, and blue Medicare card, and you also carry a Medigap card from a private insurer.

A few important limits, straight from CMS:

• Medigap only works with Original Medicare. It does not work with Medicare Advantage.
• Medigap generally does not include prescription drug coverage. For drugs, you'd add a separate Part D plan.
• Medigap does not cover long-term care, most dental, vision, hearing aids, or private-duty nursing.

Why the plans are labeled with letters

To make shopping easier, the federal government requires Medigap plans to be standardized. That means Plan G sold by one insurer covers the exact same Medicare gaps as Plan G sold by another insurer. The price and customer service can vary, but the benefits inside each letter are set by law.

In most states, including Florida, the letter options currently offered to new enrollees are:

• Plan A — the most basic set of benefits.
• Plan B — adds the Part A hospital deductible.
• Plan D — broader coverage, but no Part B deductible coverage.
• Plan G — one of the most comprehensive options for people newly eligible today.
• Plan K and Plan L — lower premiums in exchange for cost-sharing and an annual out-of-pocket limit.
• Plan M and Plan N — middle-ground options; Plan N uses small copays for some office and ER visits.

Plans C and F are still held by many longtime enrollees, but they're no longer sold to people who became eligible for Medicare on or after January 1, 2020, because those plans covered the Part B deductible.

Massachusetts, Minnesota, and Wisconsin standardize their Medigap plans differently.

What Medigap does not do

This is where a lot of confusion starts. Medigap is not the same as Medicare Advantage (Part C), and the two cannot be combined.

• If you're enrolled in a Medicare Advantage plan, you cannot use a Medigap policy to pay your Advantage plan's copays or deductibles. It's actually illegal for someone to sell you a Medigap policy when they know you have Advantage, except in narrow situations like switching back to Original Medicare.
• Medigap does not cover the 2026 Part D drug costs. Prescription drug coverage is separate, and in 2026 Part D has a $2,100 annual out-of-pocket cap and a maximum deductible of $615. The coverage gap — the old "donut hole" — was eliminated in 2025, leaving three simpler phases.
• Medigap doesn't lower your Part B premium or any Income-Related Monthly Adjustment Amount (IRMAA) surcharge, which in 2026 begins above $109,000 in income for a single filer.

When you can buy one — and why timing matters

The best window to buy Medigap is your Medigap Open Enrollment Period: the six months that start the month you're 65 or older and enrolled in Part B. During that window, insurers can't turn you down or charge more because of your health.

Outside that window, in most states, insurers can use medical underwriting. That means your health history can affect whether you're accepted and what you pay. Florida generally follows that rule, so people who miss their initial six-month window can find their choices narrower later on.

Note that Medigap has its own timing rules. It is not tied to Medicare's Annual Enrollment Period (October 15 – December 7) or the Medicare Advantage Open Enrollment Period (January 1 – March 31). Those windows are for Part D and Medicare Advantage decisions.

How this looks in North Lauderdale

North Lauderdale is in Broward County, where Medicare beneficiaries have a wide range of Medicare Advantage and Part D plan options during Annual Enrollment. Medigap works differently — the letter plans available are set at the state level, and any licensed insurer can sell them across Florida. So a North Lauderdale resident and a resident up in Coconut Creek generally see the same Medigap letter menu; what varies is the premium each company charges and how it rates policies by age.

If you want a personalized look, Florida's SHINE program (the state's SHIP) offers free, unbiased Medicare counseling to residents of Broward County and the rest of the state.