Medicare Supplement

The Medigap Chart, Decoded: What G, N, K and L Actually Do

LAKE OSWEGO, Ore. — If you have been staring at a Medigap comparison chart wondering why some columns show a checkmark, some show a percentage, and some are blank, you are not alone. The good news: federal rules do most of the heavy lifting for you. Medigap plans sold in most states are standardized by letter, which means the benefits inside Plan G, Plan N, Plan K or Plan L are set by federal standard — not by the insurance company on the envelope.

That is what this guide is about: how to read the chart, what each of those letters covers, and where the fine print actually matters.

Why the same letter means the same coverage

Medigap — also called Medicare Supplement Insurance — is regulated under federal standards described by CMS on medicare.gov. In most states, insurers can only sell plans that match one of the lettered designs: A, B, C, D, F, G, K, L, M and N, plus high-deductible versions of F and G.

The letter locks in the benefits. If two companies both sell Plan G, the medical benefits inside those two policies are identical. What can differ is the price, the customer service, how the company handles rate increases over time, and extras like a fitness perk. But the coverage itself — the part that pays your share of Medicare-approved costs — is set by the federal standard.

That is why shopping Medigap is different from shopping most insurance: you are really comparing companies, not benefits.

What Plan G covers (and what it does not)

Plan G is one of the most comprehensive letters still open to new enrollees. It covers the Part A hospital coinsurance, the Part A deductible, the Part B coinsurance or copay, the first three pints of blood, hospice coinsurance, skilled nursing facility coinsurance, Part B excess charges, and a limited foreign travel emergency benefit.

What Plan G does not cover is the Part B deductible. You pay that yourself each year before Plan G kicks in on outpatient care. It also does not cover prescription drugs — that is Part D, a separate policy.

High-deductible Plan G: same letter, different math

High-deductible Plan G covers the same list of benefits as regular Plan G, but you have to meet a plan-year deductible set by federal rule before the policy starts paying. Once you meet it, coverage looks the same as standard Plan G for the rest of the year. It is the same letter — just structured so you take on more of the early costs in exchange for a different premium arrangement.

What Plan N covers

Plan N is close to Plan G, with two important differences. First, Plan N does not pay Part B excess charges — if a provider does not accept Medicare assignment and bills above the Medicare-approved amount, you could owe that difference. Second, Plan N leaves you with small copays for some office visits and emergency room visits that do not lead to admission.

Everything else on the standardized list — Part A deductible, hospital coinsurance, Part B coinsurance (after those copays), skilled nursing coinsurance, hospice coinsurance, blood, and foreign travel emergency at the standard limit — is covered.

How Plans K and L are different

Plans K and L work on a cost-sharing model. Instead of paying most gaps in full, they pay a set percentage of certain services and leave you responsible for the rest — until you hit the plan's annual out-of-pocket limit, which is set by federal rule and updated each year. After that limit, and after the Part B deductible is met, the plan pays 100% of covered services for the rest of the calendar year.

Plan K generally pays a lower percentage than Plan L on the cost-shared items, and its yearly out-of-pocket limit is higher. Plan L pays a higher percentage and has a lower limit. Neither K nor L covers the Part B deductible or Part B excess charges.

The trade-off is the appeal: more monthly predictability in exchange for taking on more day-to-day cost sharing during the year.

Plans C and F are closed to newer enrollees

Under federal law, Plans C and F — the two letters that used to cover the Part B deductible — are no longer sold to people who became eligible for Medicare on or after January 1, 2020. If you were eligible before that date, you may still be able to buy them, depending on the state and the insurer. If you became eligible in 2020 or later, those two columns on the chart simply are not options for you.

Three states that do not use the letter chart

Massachusetts, Minnesota and Wisconsin standardize Medigap differently. The lettered chart most people see on medicare.gov does not describe how plans are structured in those states. If you live there — or are moving there — ask your State Health Insurance Assistance Program (SHIP) for the version of the chart that applies.

What this looks like from Lake Oswego

Lake Oswego is in Clackamas County, and Oregon uses the standard federal Medigap lettering. That means a Lake Oswego reader comparing Plan G quotes from three different insurers is comparing three identical benefit packages with three different price tags and companies behind them. The letter tells you the coverage; the company tells you who you will call, and what the premium looks like now and over time.

Oregon also has consumer protections around when you can switch Medigap plans. Those rules are separate from the standardized-letter rules and worth asking a licensed source about before you make a change.