Medicare Supplement Plans Cost: Average Rates & What Drives Them

Medicare Supplement insurance, also called Medigap, is sold by private insurers to cover some of the costs that Original Medicare leaves behind, such as deductibles, coinsurance, and copays. Medigap plans are standardized by letter. A Plan G from one insurer covers the same benefits as a Plan G from another, so the price is the main thing that differs.

This guide covers what each plan letter costs on average, how age affects the premium, what the lowest sample quotes look like, and which costs a Medigap policy leaves in place. Premiums here are what you pay the insurer. They are in addition to the Part B premium you pay to Medicare.

Plans with more coverage cost more. Plan A covers the core benefits, and the higher letters add coverage for the Part A deductible, skilled nursing coinsurance, and other gaps. Plan K and Plan L cover only part of those costs and cap your yearly spending, which is why their premiums sit lower.

Plan N is priced below Plan G because it has copays for office visits and some emergency room visits. Plan G has none of those copays. Plan C and Plan F are available only to people who became eligible for Medicare before 2020, so the averages for those plans apply to a smaller group.

Many Medigap policies are priced by attained age, which means the premium goes up as you get older. At 75 the averages are higher than at 65, as the plans below show.

Other policies use issue age pricing, where the premium is set by your age when you buy, or community rating, where everyone pays the same regardless of age. Attained age plans usually start lower and rise over time. A few states require community rating or a similar approach. Ask each insurer which method it uses, since the first year price can be misleading.

NerdWallet published lowest quotes for a 65 year old nonsmoker in Chicago, before any discounts. These are sample starting quotes for one profile, not averages, so they run below the national averages above.

Your own quotes will depend on your ZIP code, tobacco use, and the insurer. Rates also differ by sex in states that allow it, and some insurers offer household or automatic payment discounts.

A Medigap policy does not replace the Part B premium, and it does not include drug coverage. Plans sold to people who became eligible for Medicare after 2019 do not cover the Part B deductible.

The high-deductible version of Plan G has a low premium, but you pay covered costs yourself until you reach the deductible. After that, the plan pays the rest for the calendar year. Whether that tradeoff is worth it depends on your expected medical spending, so a SHIP counselor or licensed agent can help you weigh it.

• Plan letter: more coverage means a higher premium.
• Age and pricing method: attained age, issue age, and community rated plans move differently over time.
• Location: premiums vary by state and sometimes by ZIP code.
• Insurer: two companies can charge very different amounts for identical benefits.
• Tobacco use: many states let insurers charge smokers more.
• Enrollment timing: there is a Medigap open enrollment period after you first have Part B. After it ends, insurers in most states can use medical underwriting and may charge more or decline you.

Because benefits are standardized, you can compare policies on price alone, as long as the plan letter and pricing method match. Check how often the insurer has raised rates, ask whether there is a household discount, and confirm the policy is guaranteed renewable. The Medicare.gov plan finder lists the Medigap policies sold in your area.