Supplemental Medicare costs vary widely by plan, age, location, and insurance company

Supplemental Medicare insurance (also called Medigap) fills gaps that Original Medicare leaves open — copayments, coinsurance, and deductibles. The monthly premium you pay depends on which plan letter you choose (Plan A through Plan N are the most common), your age when you first buy it, where you live, and which insurance company sells it. There is no single price; the same Plan G might cost $120 a month in one state and $180 in another, or $95 with one insurer and $165 with another.

Most people pay between $100 and $300 per month for Medigap, though some plans cost less and some cost significantly more. Younger retirees (65 to 70) typically pay lower premiums than those who buy Medigap later in life. If you wait to buy Medigap after your initial enrollment window, you may face higher premiums or be denied coverage altogether, depending on your health and your state's rules.

Key Takeaways

  • Supplemental Medicare premiums range from roughly $100 to $300 monthly, but vary by plan type, your age, your location, and the insurance company.
  • Plan A and Plan N are typically the least expensive; Plan G and Plan F (if you are may be able to access) cover more but cost more.
  • Buying Medigap within six months of turning 65 and enrolling in Part B usually locks in lower rates and guarantees acceptance regardless of health.
  • You can switch plans or insurers during the annual open enrollment period (October 15 to December 7) without medical underwriting.
  • Your actual out-of-pocket costs depend on both the Medigap premium and how much Original Medicare costs you in deductibles and copayments.

How plan type affects what you pay

Medigap plans are standardized by the federal government, so Plan A from one company covers the same things as Plan A from another. What changes is the price. Plan A and Plan N are the entry-level options and usually have the lowest premiums — often $100 to $150 per month. Plan G is more comprehensive and typically costs $150 to $250 per month. Plan F (the most generous option) is only open to people who turned 65 before January 1, 2020, and usually costs $200 to $350 per month.

The trade-off is straightforward: a cheaper plan means you pay more out of pocket when you use medical services. Plan A covers your Part B coinsurance and copayments but leaves you responsible for the Part B deductible ($240 in 2024). Plan G covers the Part B deductible but you pay a higher monthly premium. Plan N requires you to pay copayments at the doctor's office and urgent care, but the monthly cost is lower.

To find the true cost of a plan, add the monthly premium to what you expect to spend on copayments and deductibles in a year. A cheaper plan with higher out-of-pocket costs may end up costing more if you see doctors frequently.

Age and when you buy Medigap

Insurance companies use your age to set Medigap premiums, and the difference is substantial. A 65-year-old might pay $120 per month for Plan G, while a 75-year-old pays $200 for the same plan from the same company. Waiting even a few years can add $30 to $50 to your monthly bill.

The best time to buy Medigap is within six months of turning 65 and enrolling in Medicare Part B. During this window, called the Medigap open enrollment period, insurance companies must sell you any plan at the lowest rate they offer to new customers your age, and they cannot deny you based on pre-existing conditions. If you miss this window, you enter medical underwriting — the company can ask about your health history, charge you more, or refuse to sell you a plan at all. Some states have protections that extend this window, but not all.

If you are currently on a Medigap plan and turn 65 during your coverage, you may have additional protections when switching plans, depending on your state. Check with your state's insurance commissioner's office or your State Health Insurance information Program (SHIP) to learn your specific rules.

Geographic variation in Medigap premiums

The same Medigap plan costs different amounts in different states and even different counties. A Plan G in rural Montana might cost $140 per month, while the same plan in a dense urban area of the same state could cost $200. This variation reflects local healthcare costs, competition among insurers, and state regulations.

To see what plans cost in your area, you will need to contact insurance companies directly or use the Medicare Plan Finder tool on Medicare.gov. Medicare.gov does not show Medigap prices — you must call insurers or work with a licensed insurance agent. Many agents do not charge a fee because they are paid by the insurance company, but verify this before you share personal information.

How to compare costs across plans and companies

Start by deciding which plan type makes sense for your health and budget. If you see specialists or take many medications, Plan G or Plan F (if may be able to access) may save money despite higher premiums. If you are generally healthy and want the lowest monthly cost, Plan A or Plan N might be better.

Once you have narrowed the plan type, call at least three insurance companies that sell Medigap in your state and ask for a quote for that plan. Have ready: your date of birth, the date you enrolled in Medicare Part B, your zip code, and whether you use tobacco. Quotes are free and do not obligate you to buy. Write down the monthly premium, the deductible (if any), and any waiting periods for pre-existing conditions.

After you have three quotes, calculate your estimated annual cost: (monthly premium × 12) + expected out-of-pocket costs. The cheapest premium is not always the best deal if the plan requires higher copayments or has a deductible.

When you can change plans or switch companies

If you already have Medigap and want to switch to a different plan or company, you have a may provide window once per year: October 15 to December 7. During this period, you can switch without medical underwriting, and the new coverage starts January 1. Outside this window, switching may require health questions, and some companies may deny you.

If you are still within six months of turning 65 and enrolling in Part B, you can switch anytime during that window without restrictions. After that window closes, you are limited to the annual open enrollment period unless your state has additional protections or you have a may have access to life event (such as moving to a new state where your current plan is not available).

Some states allow switching during a separate Medigap open enrollment period tied to your birthday or policy anniversary. Contact your State Health Insurance information Program to learn whether your state has this option.

Frequently Asked Questions

Is Supplemental Medicare the same as Medicare Advantage?

No. Supplemental Medicare (Medigap) works alongside Original Medicare and covers gaps in that coverage. Medicare Advantage is an alternative to Original Medicare run by private insurance companies. They are different products with different costs and coverage rules. You cannot have both at the same time.

Can I get Medigap if I have a pre-existing condition?

If you buy within six months of turning 65 and enrolling in Part B, yes — companies must sell you any plan regardless of health. If you miss that window, companies can deny you or charge more based on your medical history. Some states offer limited protections after the initial window; check with your State Health Insurance information Program.

What happens to my Medigap premium as I get older?

Premiums rise as you age, and they also increase when the insurance company raises rates for all customers in your area. The amount of increase varies by company and state. Some companies use "attained age" pricing (your premium goes up each birthday), while others use "issue age" pricing (your rate is locked to your age when you buy). Ask which method a company uses before you buy.

Do I need Medigap if I have retiree health insurance from my former employer?

Not necessarily. If your employer plan covers the gaps that Original Medicare leaves open, you may not need Medigap. However, if your employer plan ends or changes, you may have a limited window to buy Medigap without medical underwriting. Review your employer plan documents and talk to your benefits administrator before you turn 65.

Can I use the same Medigap plan if I move to a different state?

Medigap policies are not portable across state lines. If you move, you will need to buy a new policy in your new state. You may have protections during the move that allow you to switch without medical underwriting; contact your State Health Insurance information Program in your new state to learn the rules.