How Supplement Plans Work with Your Doctor

Medigap benefits are standardized by plan letter. Prices vary by insurer, age, ZIP code and tobacco use.

If your income and savings are limited, two programs can cut your Medicare costs sharply:

Those who are eligible for Medicare along with full Medicaid might also have the option of enrolling in a Dual Special Needs Plan. Learn more about help for low-income Part D beneficiaries.

A Medicare Supplement plan is built to cover the gaps in Original Medicare. These are the costs it can pick up:

Federal law sets exactly what each plan letter covers, so the same letter has the same benefits from every insurer in your state.

*Plans C and F can only be bought by people who were eligible for Medicare before January 1, 2020. **Plans K and L have a yearly out-of-pocket limit that Medicare sets each year; after you reach it, the plan pays 100% of covered services for the rest of the year. ***Plan N pays all Part B coinsurance except copays of up to $20 for some office visits and up to $50 for emergency room visits that do not lead to an inpatient admission. Massachusetts, Minnesota and Wisconsin standardize their plans differently.

These three are the usual picks for people just starting on Medicare. With Plan G, every gap is covered apart from the Part B deductible. Plan N charges a smaller premium in exchange for copays as high as $20 for certain office visits and as high as $50 for ER trips that do not end in admission, and it leaves Part B excess charges uncovered. For 2027, High-Deductible Plan G carries a $3,050 deductible, rising from $2,950, after which it pays like Plan G. Read Plan G vs Plan N.

The method depends on the insurer and the state. Ask how a policy is priced before you buy, not just what it costs today.

For 2027, a standalone Part D plan has a maximum deductible of $700 and an out-of-pocket cap of $2,400. Buy one when you buy Medigap to avoid a lifelong late enrollment penalty.

Plans K and L pay a share of most costs instead of all of them: Plan K pays 50% and Plan L pays 75% of most cost sharing, after which you pay the rest. In exchange for lower premiums, both have a yearly out-of-pocket limit that Medicare sets each year. Once you reach it, the plan pays 100% of covered services for the rest of the year.

These plans can suit people who want catastrophic protection at a lower premium and can handle some costs along the way. Ask whether your insurer offers Plan K or L in your state.

Plans C and F are the only plans that cover the Part B deductible. Since January 1, 2020, they cannot be sold to people newly eligible for Medicare. If you were eligible for Medicare before that date, even if you did not enroll, you may still be able to buy Plan C or F, including a High-Deductible Plan F with the same $3,050 deductible for 2027.

For most people who can buy either, compare the yearly premium difference between Plan F and Plan G with the Part B deductible. If Plan F costs more than the deductible saves you, Plan G is the better value.

If you have Medicare before 65 because of a disability or end-stage renal disease, federal law does not require insurers to sell you a Medigap policy, but many states do. Prices for people under 65 can be much higher, and plan choices may be limited. When you turn 65, you get a new six-month Medigap Open Enrollment Period, when you can buy any plan sold in your state at the same prices as everyone else your age.

Inside the U.S., a Medigap plan follows you everywhere, because it works with any provider that accepts Medicare. Outside the U.S., Original Medicare generally pays nothing, but Plans C, D, F, G, M and N cover 80% of emergency care abroad after a $250 yearly deductible, up to a $50,000 lifetime limit.

Medigap benefits never change once you buy, but premiums can. Insurers file rate increases with state regulators, often once a year. Because the same plan letter covers the same benefits everywhere, switching to a lower-priced insurer can save money without changing your coverage.

The catch is underwriting. Outside your Medigap Open Enrollment Period or a guaranteed issue situation, most states let the new insurer ask health questions and decline you. Never cancel your current policy until the new one is approved and in force.

In most cases you never file a Medigap claim. Your doctor bills Medicare, Medicare pays its share, and the claim crosses over to your Medigap insurer automatically, which pays its share. You get a Medicare Summary Notice and an explanation of benefits showing what each paid.

You do not have to compare plans alone, and you should not have to pay for help. These are the free options:

Before any call, have your Medicare card, your list of drugs and doses, your doctors and your preferred pharmacies ready. It turns a long conversation into a short one.