How to choose a Medicare Supplement plan without getting talked into the wrong one

How to choose a Medicare Supplement plan without getting talked into the wrong one

Ten Medigap plans are sold under standard letter names from A to N, and they're identical from carrier to carrier. The only thing that changes between insurance companies is the price. Here's how to pick.

Pick up the phone after you turn 64 and a half. You'll get calls. A lot of calls. Every one is from someone who says they want to help you with Medicare. What they want is to sell you something.

Medicare Supplement insurance, also called Medigap, is one of the easier insurance products to understand if someone walks you through it without trying to close a deal in the same conversation. So let's do that.

What Medigap actually does

Original Medicare (Parts A and B) pays roughly 80 percent of your covered medical costs. The other 20 percent is on you, with no annual cap. On a normal year that's fine. On a bad year (cancer treatment, heart surgery, long hospital stay) the 20 percent can run into tens of thousands.

Medigap fills in that 20 percent. You pay a monthly premium, and in exchange the Medigap insurer picks up most or all of your share of Medicare-approved charges.

You only need Medigap if you have Original Medicare. If you choose Medicare Advantage instead, you can't buy a Medigap policy. The two are mutually exclusive.

The ten plans are standardized

Here's the thing the insurance industry doesn't lead with: every Medigap plan with the same letter offers identical benefits. Plan G from Aetna is the same as Plan G from Mutual of Omaha is the same as Plan G from Cigna. Down to the comma.

What changes between insurance companies is price. Sometimes by hundreds of dollars a month for the exact same coverage. That's the whole game. Find the cheapest carrier for the plan letter you want from a company that's financially solid.

Plan G is the one most people pick

Plan G covers everything except the annual Part B deductible ($283 in 2026). After you pay that one deductible, your Medicare costs for the year are essentially zero. No copays for doctor visits, no coinsurance for hospital stays, no surprise bills.

Plan G is the gold standard for people who want to never think about Medicare bills again. Premiums vary by zip code and age, but most people pay between $130 and $220 a month at age 65.

Plan N is the budget version

Plan N is the next most popular option, and it's typically $30 to $50 a month cheaper than Plan G. The tradeoffs are small but real.

$20 copay for office visits

$50 copay for ER visits that don't result in admission

Does not cover Part B excess charges (more on that below)

For someone who doesn't see the doctor much, Plan N saves real money. For someone with chronic conditions who's at the office monthly, the copays add up and Plan G usually wins.

The Part B excess charge trap

Most doctors accept Medicare assignment, meaning they accept what Medicare pays as full payment. Some don't. The ones that don't can charge up to 15 percent above the Medicare-approved rate, and that 15 percent is on you. Unless you have Plan G or Plan F, which cover it.

If you live in an area where most doctors accept assignment (rural Texas, most of the Midwest), excess charges are rare and Plan N is fine. If you live somewhere with a lot of specialty practices that don't (parts of New York, Boston, San Francisco), Plan G is the safer pick.

Eight states ban excess charges entirely: Connecticut, Massachusetts, Minnesota, New York, Ohio, Pennsylvania, Rhode Island, and Vermont. In those states, Plan N is functionally as good as Plan G for less money.

How carriers price the same plan differently

Medigap pricing comes in three flavors. Knowing which one a carrier uses tells you what your premium will do over time.

Community-rated: everyone in your area pays the same premium regardless of age. The premium goes up with inflation, not with your birthday.

Issue-age-rated: your premium is locked to your age when you bought it. A 65-year-old today and a 65-year-old next year pay the same starting rate. The premium still goes up with inflation, but not because you got older.

Attained-age-rated: this is the trap. The premium starts low when you buy it at 65, then goes up every year as you age. By 80, it can be triple what you started at. Most cheap-looking premiums you see advertised are attained-age.

Ask the agent which pricing model the carrier uses. If they don't know or won't say, hang up.

The six-month enrollment window

This is the most important thing in the whole article. The day you turn 65 and enroll in Part B, you have a six-month window during which Medigap carriers must sell you any plan they offer, at their standard rate, with no health questions asked.

After those six months close, the rules change. Insurance companies can ask about your medical history. They can charge you more. They can deny you outright. There are some state-level exceptions, but the federal rule is brutal: miss your window, lose your easy enrollment.

If you're approaching 65, plan to enroll within those six months. Even if you don't think you need Medigap yet, the cost of waiting can be that you can't get it later.

What to do next

Use the Medicare.gov plan finder or call your State Health Insurance Assistance Program (SHIP). SHIP counselors are free, they're not paid on commission, and they have no incentive to push one carrier over another. Find your local SHIP at shiphelp.org.

When you're ready to compare carriers, get quotes from at least three: a national carrier (Mutual of Omaha, Aetna, Cigna), a Blue Cross Blue Shield plan for your state, and one regional carrier. Compare Plan G prices specifically. If one is dramatically cheaper than the other two, ask why.

Don't sign anything in the same conversation you got the quote. Sleep on it. The good agents understand that. The bad ones won't, and that's information too.

Sources

1. Medicare.gov, How to compare Medigap policies. medicare.gov/health-drug-plans/medigap

2. Centers for Medicare & Medicaid Services, 2026 Medicare Parts A & B Premiums and Deductibles, November 2025. cms.gov

3. State Health Insurance Assistance Program (SHIP) National Technical Assistance Center. shiphelp.org