Medicare Supplement

Making Sense of Medigap: What Those Plan Letters Mean

MASON, Ohio — If you've started shopping for a Medicare Supplement policy, you've probably run into a confusing alphabet: Plan A, Plan G, Plan N, and a few others. Those letters aren't random. They're the backbone of how Medigap works, and once you understand them, comparing your options gets a lot simpler.

Here's a plain-language guide to what Medigap does, why the letters matter, and how to think through your choice.

What Medigap actually does

Medigap — short for Medicare Supplement Insurance — is a private policy that works alongside Original Medicare (Part A and Part B). After Medicare pays its share of a covered service, your Medigap plan helps pay some of what's left, like coinsurance, copays, and deductibles.

A few important points:

• Medigap only works with Original Medicare. It does not pair with a Medicare Advantage plan.
• Medigap does not include prescription drug coverage. For that, you'd add a separate Part D plan.
• You pay a monthly premium to the insurance company for the Medigap policy, on top of your Part B premium.

Why the letters exist

In most states, Medigap plans are standardized by the federal government. That means Plan G from one insurance company covers the same basic benefits as Plan G from another. The price can differ, and the customer service can differ, but the core benefits are set by Medicare.

There are 10 standardized letter plans available in most states: A, B, C, D, F, G, K, L, M, and N. (Massachusetts, Minnesota, and Wisconsin standardize their plans differently.) You can review the full benefit chart on medicare.gov.

What changed with Plans C and F

If you became eligible for Medicare on or after January 1, 2020, you cannot buy Plan C or Plan F. Those plans covered the Part B deductible, and federal law no longer allows newly eligible enrollees to purchase plans that do that. People who were already eligible before that date can still buy or keep them.

For most newer enrollees, that's why Plan G and Plan N get a lot of attention — they're the closest remaining options in terms of broad coverage.

How to think about picking a letter

There's no single "right" Medigap plan. The letters are really a menu of trade-offs between monthly premium and out-of-pocket exposure. A few honest questions can help:

• How predictable do you want your costs to be? Plans with more complete coverage usually have higher premiums but fewer surprises at the doctor's office.
• How often do you expect to use care? If you see specialists often, a plan that covers more coinsurance may feel worth the higher premium.
• Are you healthy now but planning for later? Your best pricing and guaranteed acceptance usually happen during your one-time Medigap Open Enrollment Period — the six months that start when you're 65 or older and enrolled in Part B. Outside that window, insurers in most states can use medical underwriting.

Where Medigap fits in the bigger 2026 picture

Medigap sits on the Original Medicare side of the road. On the other side is Medicare Advantage (Part C), which bundles your coverage through a private plan. You choose one path or the other — not both.

Mason is in Warren County, where residents have access to a range of Medicare Advantage and Part D plans through the Medicare marketplace. If you go the Original Medicare + Medigap route, you'll also want to think about a Part D drug plan. For 2026, Part D has a $2,100 annual out-of-pocket cap on covered drugs, a maximum deductible of $615, and an optional Medicare Prescription Payment Plan that lets you spread drug costs across the year. The old "donut hole" coverage gap was eliminated in 2025, so Part D now runs in three phases.

Higher-income enrollees should also know about IRMAA, an income-based surcharge that starts above $109,000 for a single filer in 2026 and adds to Part B and Part D premiums.

Key enrollment windows to keep in mind

• Medicare Annual Enrollment Period: October 15 – December 7 (for Part D and Medicare Advantage changes).
• Medicare Advantage Open Enrollment: January 1 – March 31.
• Medigap Open Enrollment: Your personal six-month window that begins the month you're 65 or older and enrolled in Part B. This is the friendliest time to buy a Medigap policy in most states.