There is no single "best" plan — the right one depends on your health, budget, and how often you see doctors

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 premiums each month and which gaps each plan covers. Plan G covers more than Plan N, which covers more than Plan A. A plan that is "best" for someone who sees a specialist every month may be wasteful for someone who rarely needs care. The choice comes down to three questions: How much can you afford to pay monthly? How much medical care do you typically use? And how much do you want to protect yourself against unexpected costs?

The federal government standardizes all Medigap plans, so Plan G from one insurance company covers exactly the same things as Plan G from another — only the monthly premium differs. This means you are not comparing different benefits; you are comparing price and deciding which level of coverage matches your needs.

Key Takeaways

  • Medicare Supplement plans are standardized by the federal government, so Plan G from one insurance company covers exactly the same things as Plan G from another — only the monthly premium differs.
  • Plans with higher monthly premiums (like Plan G) cover more of your out-of-pocket costs, while plans with lower premiums (like Plan A) leave you paying more when you need care.
  • You can switch plans during the annual open enrollment period (October 15 to December 7) without being denied for pre-existing conditions, but switching outside that window may require medical underwriting.
  • The plan that costs the least per month is not always the cheapest over a year if you use significant medical care, because lower-premium plans make you pay more at the doctor's office.
  • Your age when you first buy a Medigap plan affects your premium for life, so buying at 65 costs less than buying at 72, even if you switch plans later.

How the most common plans compare

The federal government defines ten standardized Medigap plans, labeled A through N. Most people choose from four: Plan A, Plan G, Plan N, and Plan F (though Plan F is only open to people who turned 65 before January 1, 2020). Each plan covers a different combination of the costs Medicare does not pay.

Plan A is the least expensive monthly but leaves you paying the Part B deductible ($240 in 2024, though this amount changes yearly) and 20 percent coinsurance for most services. Plan G costs more per month but covers the Part B deductible and most coinsurance, leaving you responsible mainly for copayments at the doctor. Plan N is between them — lower premium than G, but you pay small copayments ($20 for office visits, $50 for emergency room) and the Part B deductible. Plan F covers nearly everything but is closed to new buyers under 65.

The right choice depends on your pattern of care. If you have arthritis and see your rheumatologist monthly plus a primary care doctor quarterly, Plan G or F probably saves you money overall despite the higher premium. If you see a doctor once a year for a checkup, Plan A's lower premium likely costs less in total. The key is to add up what you would pay in premiums plus out-of-pocket costs under each plan, not just look at the monthly premium alone.

What your age and timing mean for your cost

Insurance companies can charge you based on your age when you buy a Medigap plan. Most use "attained age" pricing, meaning your premium goes up as you get older. A few use "issue age" pricing, where your premium is locked to your age when you buy and does not increase as you age — but you pay more upfront. Some use "community rated" pricing, where everyone in your state pays the same regardless of age.

The timing of your purchase matters permanently. If you buy Plan G at 65, your premium at 75 will be lower than someone who bought the same plan at 72. This is why financial advisors often recommend buying a Medigap plan as soon as you turn 65 and enroll in Medicare Part B, even if you are still working and have employer coverage — you lock in the lowest age-based rate.

You can switch between plans during the annual open enrollment period (October 15 through December 7) without the insurance company asking about your health. Outside that window, they may require medical underwriting, meaning they can deny you or charge more if you have a pre-existing condition. Some states have additional protections that allow switching at other times, so check your state's rules before you assume you are locked into your current plan.

How to compare premiums in your area

The same Medigap plan costs different amounts depending on which insurance company sells it and where you live. Plan G from Aetna might cost $150 a month in one county and $180 in the next. You cannot find a single "best price" — you have to compare quotes from multiple insurers in your zip code.

Medicare.gov has a tool called the Medigap Plan Finder where you enter your state and zip code and see plans and premiums from insurers in your area. You can also call insurers directly or work with a licensed insurance agent (many do not charge you — they are paid by the insurance company). An agent can be helpful if you are unsure which plan type suits you, though remember they may earn higher commission on certain plans.

When comparing, look at the premium for the first year and ask what the company's history is for raising rates. Some companies raise premiums 5 percent yearly; others raise 10 percent or more. A plan that is cheapest today may not be cheapest in five years, so ask about the company's track record before you decide.

When to buy and when you cannot be turned down

You have the strongest legal protection to buy a Medigap plan during your "open enrollment period," which starts the month you turn 65 and enroll in Medicare Part B. During this six-month window, insurance companies must sell you any plan and cannot charge more or deny you based on health. This protection is federal law.

If you miss that window, you can still buy during the annual open enrollment period each October through December, but outside those times, insurers can medically underwrite you — meaning they can refuse to sell you a plan, charge a higher premium, or exclude certain conditions. Some states have additional protections; a few allow you to switch plans at any time, while others have limited windows. Check your state's insurance commissioner's office for your specific rules.

If you have employer coverage when you turn 65, you may be able to delay buying Medigap without losing your open enrollment protection, but the rules are complex and depend on your employer's plan. Talk to your employer's benefits administrator before you turn 65 to understand whether you can keep your employer coverage and delay Medigap, or whether you need to buy Medigap to avoid penalties.

Questions to ask yourself before choosing

Before you settle on a plan, write down the answers to these questions. They will guide you toward the right choice for your situation.

How much can you afford to pay monthly? List your fixed income or budget. Medigap premiums range from roughly $100 to $300 a month depending on the plan and your age. If you cannot afford more than $120, Plan A or N may be your only option, even if Plan G would save money overall.

How often do you see doctors, and for what? If you manage multiple chronic conditions (diabetes, heart disease, arthritis), you likely have regular appointments and specialist visits. Higher-coverage plans save you money. If you are generally healthy and see a doctor once yearly, a lower-premium plan may be better. Write down your appointments from the past year to get an honest picture.

Do you take many medications? Medigap does not cover prescription drugs — that is Part D. But if you need frequent lab work or imaging to manage your medications, a plan that covers coinsurance (like G or F) reduces your costs. If you rarely need tests, the coinsurance coverage matters less.

How much financial risk can you tolerate? Plan A leaves you paying the Part B deductible ($240) and 20 percent of most costs. If an unexpected hospitalization or surgery happens, you could owe thousands. Plan G caps your out-of-pocket costs much lower. If the thought of a large medical bill causes stress, a higher-coverage plan is worth the premium.

What happens if you switch plans later

You can change Medigap plans, but the process and your costs depend on when you switch. During the annual open enrollment period, you can switch to any plan without medical underwriting. Outside that window, the new insurance company can review your health history and may deny you, charge more, or exclude pre-existing conditions.

Your new plan's premium will be based on your current age, not the age you were when you first bought Medigap. If you bought Plan A at 65 and switch to Plan G at 72, you will pay the Plan G premium for a 72-year-old, not a 65-year-old. This is why buying the right plan the first time matters — switching later costs more.

Some people buy Plan A at 65 because it is cheap, then switch to Plan G at 70 when they develop health conditions. This works during open enrollment, but it costs more than buying Plan G at 65 would have. If you think you might want more coverage later, buying a higher-coverage plan at 65 may be cheaper over your lifetime, even though the monthly premium is higher now.

Frequently Asked Questions

Does Medicare Supplement cover prescription drugs?

No. Medigap covers copayments and coinsurance for medical services, but not medications. You need a separate Part D prescription drug plan for that. You can have both a Medigap plan and a Part D plan at the same time.

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

No. You choose either Original Medicare plus a Medigap plan, or a Medicare Advantage plan. You cannot have both. If you have a Medigap plan and switch to Medicare Advantage, you must drop the Medigap plan.

What if I cannot afford any Medigap plan?

Some states offer programs that help low-income seniors pay Medigap premiums. Contact your State Health Insurance information Program (SHIP) — you can find yours at shiptalk.org or by calling 1-877-839-2675. You might also consider a Medicare Advantage plan, which typically has lower or no monthly premiums, though you pay more per visit.

Will my Medigap premium go up every year?

Yes, most companies raise premiums annually. The amount varies — some raise 3 to 5 percent yearly, others raise 8 to 10 percent or more. When you compare plans, ask the insurance company about their historical rate increases. Over time, a plan with a slightly higher starting premium but lower increases may cost less than a cheaper plan with steep annual hikes.

What should I do if I think I chose the wrong plan?

If you are within your first 30 days of buying a Medigap plan, you have a "free look" period where you can cancel and get your money back. After that, you can switch plans during the annual open enrollment period without medical underwriting. Outside open enrollment, switching may require medical approval. Contact your state's insurance commissioner's office if an insurer denies you a switch.