There is no single best plan — it depends on what you spend on healthcare

The "best" Medicare Supplement plan is the one that covers the gaps you actually use. Medicare Part A and Part B leave you responsible for deductibles, coinsurance, and copayments. A Medigap plan fills some or all of those gaps. Which plan does that depends on how often you see doctors, whether you travel, and how much you can afford to pay in premiums each month.

The ten standardized Medigap plans available in most states are labeled A through N. Each one covers a different combination of gaps. Plan G covers the most (except the Part B deductible), Plan A covers the least, and the others fall in between. A plan that looks expensive in monthly premium might save you thousands if you have chronic conditions and see specialists regularly. A cheaper plan might be right if you are healthy and rarely need care.

Your state, age, and health history affect which plans are sold to you and what you pay. Some insurers will not sell you a plan if you have had certain diagnoses. The best approach is to list the plans available to you, estimate your annual healthcare costs under each one, and pick the plan where your premium plus expected out-of-pocket costs add up to the lowest total.

Key Takeaways

  • Medigap plans A through N each cover different combinations of Medicare's gaps, and the "best" plan depends on how much healthcare you use and what you can afford in premiums.
  • Plan G covers the most gaps for the fewest out-of-pocket costs, but costs more in monthly premiums than plans A, B, or C.
  • Plans F and J are no longer sold to people new to Medicare, though people who had them before 2020 can keep them.
  • You can compare the same plan across different insurers in your state — the coverage is identical, but the premium price varies widely.
  • Open enrollment for Medigap runs from your 65th birthday month through the end of that month plus eight months, and insurers cannot deny you or charge more based on health during this window.

What each Medigap plan covers

The ten plans are standardized, meaning Plan G from one insurer covers exactly the same things as Plan G from another. The differences are in the monthly premium you pay. Here is what the most common plans cover:

Plan A covers Part A coinsurance and hospital costs after Medicare stops paying, Part B coinsurance and copayments, and blood transfusions. It does not cover the Part B deductible or excess charges. It is the cheapest plan but leaves you responsible for more out-of-pocket costs.

Plan G covers everything Plan A does, plus the Part B deductible, excess charges, and foreign travel emergencies. It does not cover the Part A deductible. Plan G is the most popular choice because it covers most gaps without being the most expensive option.

Plan N covers Part A coinsurance, Part B coinsurance and copayments, Part A deductible, and foreign travel emergencies. You pay a copayment for some doctor visits and emergency room visits. Plan N has lower premiums than Plan G but higher out-of-pocket costs when you use care.

Plans B, C, D, K, L, and M exist but are less commonly chosen. Plan B covers the Part A deductible but not the Part B deductible. Plan C is similar to Plan G but covers the Part A deductible instead of the Part B deductible. Plans D, K, and L cover different combinations of the deductibles and have varying copayments. Plan M covers the Part A deductible and half the Part B deductible.

Plans F and J are no longer sold to anyone who turns 65 or becomes Medicare-may be able to access after January 1, 2020. If you had one of these plans before that date, you can keep it, but you cannot switch to it if you do not already have it.

How to estimate your total cost under each plan

The monthly premium is only part of what you pay. You also pay out-of-pocket costs when you use care. To compare plans fairly, add up what you would pay in a year under each one.

Start by listing the healthcare you expect to use in the next year. If you have diabetes, heart disease, or another chronic condition, look at how many doctor visits, specialist visits, and hospital stays you had in the past year. If you are generally healthy, use a conservative estimate — perhaps two primary care visits and one specialist visit.

For each plan, calculate: (monthly premium × 12) + (expected out-of-pocket costs). For example, if Plan G costs $150 a month and you expect to pay $500 in copayments and coinsurance, your total is $2,300. If Plan N costs $100 a month and you expect to pay $800 in copayments, your total is $2,000. In this case, Plan N would cost less overall, even though the monthly premium is lower.

This calculation is approximate because you cannot predict exactly how much care you will need. But it gives you a realistic sense of which plan will cost you the least in a typical year. If you are uncertain about your healthcare needs, Plan G is usually a safe middle ground — it covers most gaps without the highest premium.

When you can buy a Medigap plan and what insurers can charge

You have a six-month window when insurers cannot deny you coverage or charge you more because of health problems. This window is called the Medigap open enrollment period, and it starts the month you turn 65 and are enrolled in Medicare Part B. It lasts through the end of that month plus eight more months.

If you buy a plan during this window, the insurer must sell it to you at the standard rate for your age and location, regardless of your medical history. If you wait until after this window closes, insurers can refuse to sell you a plan or charge you a higher premium based on your health. Some states have additional protections, but the federal may provide ends after those nine months.

You can also buy a Medigap plan during the annual Medicare open enrollment period (October 15 to December 7), but outside of your initial enrollment window, insurers can use medical underwriting — meaning they can deny you or charge more based on your health status.

How to find and compare plans in your state

The plans sold in your state depend on state law. Some states allow all ten plans; others restrict which ones insurers can sell. Your first step is to find out which plans are actually available to you.

Contact your state's health insurance counselor through your State Health Insurance information Program (SHIP). SHIP is free and has counselors in every state who can tell you which plans are sold in your area and help you compare them. You can find your state's SHIP office at shiptalk.org or by calling 1-877-839-2675.

Once you know which plans are available, get quotes from at least three insurers for each plan you are considering. The coverage is identical across insurers, but premiums vary. Some insurers offer discounts for paying annually instead of monthly, or for setting up automatic payments. Compare the total annual cost, not just the monthly premium.

You can also use Medicare.gov's plan comparison tool, though it does not show all insurers in every state. SHIP counselors often have more complete local information.

Common reasons people switch plans and when you can do it

You can switch Medigap plans once a year during the annual Medicare open enrollment period (October 15 to December 7). Your new coverage starts January 1. Outside of this window, you can switch plans only if you have a may have access to life event — you move to a different state, your current insurer stops selling Medigap in your area, or your insurer raises rates significantly.

Many people switch because their healthcare needs change. If you develop a chronic condition and start seeing specialists more often, a plan with lower out-of-pocket costs might save you money even if the premium is higher. If you retire and move to a different state, you may need to switch because not all insurers sell in all states.

Some people switch to save money on premiums. Insurers sometimes raise rates for existing customers while offering lower rates to new ones. If you have been with the same insurer for years and their rates have climbed, getting quotes from competitors during open enrollment might reveal a cheaper option.

What Medigap does not cover

Medigap covers gaps in Medicare Part A and Part B, but it does not cover dental, vision, hearing aids, or long-term care. It also does not cover prescription drugs — that is covered by Medicare Part D, which you buy separately.

If you need dental or vision coverage, you have to buy a separate plan or pay out of pocket. Some Medicare Advantage plans (Part C) include dental and vision, but they have different rules and networks than Medigap. If prescription drug coverage is important to you, you must enroll in Part D during your initial enrollment window or pay a penalty if you join later.

Frequently Asked Questions

Is Plan G always better than Plan A because it covers more?

Not necessarily. Plan G covers more gaps, so your out-of-pocket costs are lower when you use care. But Plan G's monthly premium is usually $50 to $100 higher than Plan A. If you rarely see doctors, the lower premium of Plan A might cost you less overall, even though you pay more when you do need care. Calculate your expected total cost under each plan to decide.

Can I switch from one Medigap plan to another if my health gets worse?

You can switch during the annual open enrollment period (October 15 to December 7) without medical underwriting. Outside of that window, insurers can deny you or charge more based on your health. If your health changes significantly, ask your SHIP counselor whether your state has additional protections that might let you switch.

What happens if I do not buy a Medigap plan when I turn 65?

You can still buy one later, but you lose your protection against medical underwriting. Insurers can refuse to sell you a plan or charge you a higher premium based on your health history. If you think you might want Medigap, it is usually cheaper to buy during your initial enrollment window, even if you do not think you need it yet.

Can I have both a Medigap plan and a Medicare Advantage plan?

No. You can have either Medigap (Part A, Part B, and Part D) or Medicare Advantage (Part C), but not both. If you have Medigap and want to switch to Medicare Advantage, you can do so during open enrollment. If you switch back to Medigap later, you may face medical underwriting unless you have a may have access to life event.

Do all insurers sell all Medigap plans in my state?

No. Each insurer decides which plans to sell, and different insurers sell different plans in the same state. Some insurers sell all ten plans; others sell only three or four. This is why getting quotes from multiple insurers is important — the plan you want might not be available from every company.