There is no single "best" Medicare Supplement — the right one depends on what you spend on healthcare and which doctors you see

Medicare Supplement plans (also called Medigap) all cover the same gaps in Original Medicare: copayments, coinsurance, and deductibles. The difference is how much you pay in monthly premiums and which gaps each plan covers. Plan G covers more than Plan N, but costs more per month. Plan N costs less but leaves you responsible for some copayments at the doctor's office. The "best" plan is the one where your total yearly cost — premiums plus out-of-pocket expenses — is lowest for your situation.

Your choice also depends on whether you want to see any doctor who accepts Medicare (Original Medicare route) or stick to a network (Medicare Advantage route). This article covers Medigap, which pairs with Original Medicare and lets you see any Medicare provider nationwide. If you are already in Medicare Advantage, you cannot buy Medigap; if you are in Original Medicare and want to switch to Advantage, you must drop Medigap first.

Key Takeaways

  • The 10 standardized Medigap plans (A, B, D, G, K, L, M, N, and two high-deductible versions) cover the same benefits within each letter — the insurer does not matter, only the plan letter and your age.
  • Plan G and Plan N are the most common because Plan G covers nearly everything but costs more, while Plan N costs less but leaves copayments for doctor visits and emergency room use.
  • Your monthly premium depends on your age, where you live, and which insurance company sells the plan — the same Plan G can cost $100 or $200 per month depending on the insurer.
  • You can only buy Medigap during your initial enrollment window (the six months after you turn 65 and enroll in Medicare Part B) without medical underwriting; outside that window, insurers can deny you or charge more based on your health history.
  • Comparing total yearly cost — premiums plus expected out-of-pocket expenses — matters more than picking the plan with the lowest premium, because a cheaper plan may leave you paying thousands more at the doctor.

The 10 Medigap plans and what each one covers

Medicare offers 10 standardized Medigap plans labeled A through N (with two high-deductible versions of G and F). Every insurance company selling Plan G must cover exactly the same benefits; the only differences are the monthly premium and customer service. This means you are not choosing between plans based on coverage — you are choosing based on price and which gaps in Medicare matter most to you.

Plan A is the most basic and cheapest. It covers the Part B deductible, copayments, and coinsurance, but not the Part A deductible or skilled nursing facility coinsurance. Plan B covers more, including the Part A deductible. Plan D, K, and L cover varying amounts of the Part A deductible and skilled nursing facility costs. Plan G covers almost everything except the Part B deductible (which is $240 in 2024, though this changes yearly). Plan N is similar to G but leaves you paying copayments at the doctor ($20 typical) and emergency room ($50 typical) and does not cover the Part B excess charge (the amount some doctors bill above Medicare's approved amount).

High-deductible Plan G and high-deductible Plan F have much lower monthly premiums but require you to pay a deductible (around $2,700 in 2024) before the plan covers anything. These make sense only if you are healthy and do not expect major medical expenses in a given year. Plans D, K, and L are rarely chosen today because Plan G and Plan N offer better value for most people.

Plan G versus Plan N: the most common choice

Most people choosing Medigap narrow it down to Plan G or Plan N. Plan G costs more per month but covers the Part B deductible and all copayments and coinsurance. Plan N costs less per month but leaves you paying a copayment (usually $20) when you see a doctor, $50 for an emergency room visit (waived if admitted), and any amount a doctor charges above Medicare's approved rate.

To decide between them, estimate your yearly healthcare spending. If you see doctors frequently or expect surgery, Plan G's higher premium may save you money overall because you avoid copayments. If you are healthy and rarely see a doctor, Plan N's lower premium may be worth the copayments you will owe. A rough break-even point is around 10 to 15 doctor visits per year, depending on your local premiums, but this varies widely by region and insurer.

Plan G also gives you peace of mind: you know exactly what you owe (your premium) and Medicare covers the rest. Plan N requires you to track copayments and watch for excess charges, which adds complexity. Some people choose Plan G straightforward for that certainty, even if Plan N might save a few dollars in a good year.

How premiums are set and why they vary so much

The same Plan G from two different insurers can cost $100 per month from one company and $200 from another. Premiums depend on three things: the plan letter (G costs more than N), your age, and your location. Some insurers also use your health history to set premiums, though only during certain enrollment windows.

Insurers use three pricing methods: community-rated (everyone in your area pays the same, regardless of age), age-rated (premiums rise as you age), and issue-age-rated (your premium is based on your age when you first buy the plan and stays locked in, though it rises with inflation). Age-rated plans are usually cheapest at 65 but cost more as you age. Issue-age-rated plans cost more upfront but do not jump as you get older. Community-rated plans fall somewhere in between.

Your location matters because insurers price plans differently by state and sometimes by county. A Plan G in rural Montana may cost half what the same plan costs in New York City. This is why comparing quotes from multiple insurers in your area is essential — you can save hundreds per year by shopping around.

When you can buy Medigap and what happens if you miss the window

You have the strongest protection during your initial enrollment window: the six months starting the month you turn 65 and enroll in Medicare Part B. During this window, insurers must sell you any Medigap plan at the standard rate, regardless of your health history. This is called may provide issue rights.

If you miss this window, you can still buy Medigap, but insurers can refuse to sell to you, charge you more based on your health, or impose a waiting period for pre-existing conditions. Some states have additional protections — for example, if you were in Medicare Advantage and switch back to Original Medicare, you may have a second may provide issue window — but these vary. The safest approach is to buy during your initial window, even if you are not sure which plan you want. You can switch plans later without penalty.

If you are already past your initial window and want to buy Medigap, contact insurers directly and ask what they will offer. Some will still sell to you at standard rates; others will not. Getting turned down by one company does not mean all will refuse, so shop multiple insurers before assuming you cannot buy.

Comparing plans and getting quotes

Start by deciding which plan letter makes sense for your situation: Plan G if you see doctors often or want simplicity, Plan N if you are healthy and want the lowest premium, or Plan A if you want the absolute cheapest option and do not mind higher out-of-pocket costs. Once you have picked a plan letter, get quotes from at least three insurers in your area. Most insurers let you quote online without providing personal information.

When comparing quotes, look at the total yearly cost: monthly premium times 12, plus your expected out-of-pocket expenses (copayments, deductibles, and excess charges). A plan with a $20 lower monthly premium but $500 more in copayments costs you $260 more per year. Spreadsheet the numbers if you are comparing more than two plans.

Also check whether the insurer has a good reputation for paying claims and handling customer service. The National Association of Insurance Commissioners (NAIC) publishes complaint data by company and state. A very cheap plan from an insurer with many complaints may cost you time and frustration.

Switching plans and what it costs

You can switch from one Medigap plan to another at any time, but the rules depend on when you switch. During your initial enrollment window (the first six months after you turn 65 and enroll in Part B), you can switch plans without medical underwriting. Outside that window, you can still switch, but the new insurer can deny you or charge more based on your health.

Some states have open enrollment periods for Medigap — usually in the fall — when you can switch plans without medical underwriting, even if you are past your initial window. Check with your state insurance commissioner's office to see if yours does. If your state does not have an open enrollment period and you want to switch outside your initial window, contact the new insurer first and ask whether they will take you before you cancel your current plan. Do not cancel until you know the new plan will accept you.

Switching plans does not affect your Medicare coverage; you stay in Original Medicare the whole time. Your new Medigap plan straightforward takes over from the old one on the date you choose.

Frequently Asked Questions

Can I have both Medigap and Medicare Advantage at the same time?

No. You must choose one or the other. If you are in Original Medicare with Medigap and want to switch to Medicare Advantage, you must cancel Medigap first. If you are in Medicare Advantage and want to switch to Original Medicare with Medigap, you can buy Medigap during the switch, and you will have may provide issue rights for 63 days after your Advantage plan ends.

What if I buy a Medigap plan and then decide I do not like it?

Most states give you a 30-day free look period after you buy a Medigap plan. If you cancel within that window, you get your premiums back and can buy a different plan. After 30 days, you can still switch, but the new insurer can deny you or charge more based on your health, unless you are in your initial enrollment window or your state has an open enrollment period.

Do I need Medigap if I am still working and have employer health insurance?

Not necessarily. If your employer plan is primary (pays first), you may not need Medigap. However, when you retire and lose that coverage, you will have a may provide issue window to buy Medigap without medical underwriting. Talk to your employer's benefits office about your options and the timing of your coverage change.

Will my Medigap premium go up every year?

Yes, but how much depends on the pricing method the insurer uses. Age-rated plans rise faster as you get older. Issue-age-rated plans rise more slowly because your age is locked in. Community-rated plans may rise based on inflation or claims experience in your area. Expect annual increases of 3 to 8 percent, though some years are higher.

What happens to my Medigap plan if I move to a different state?

Your current plan ends when you move. You will need to buy a new Medigap plan in your new state, and the new insurer can deny you or charge more based on your health unless you are in your initial enrollment window. Some states have protections for people moving into the state; check with your new state's insurance commissioner's office. Plan ahead before you move so you are not without coverage.