What Is the Average Cost of Medicare Supplement Insurance? The Latest National Data

KFF reports averages for everyone holding a policy in a given year, including people who bought years ago and people under 65. Three snapshots show the direction clearly.

Source: KFF analysis of Mark Farrah Associates Medicare Supplement data from NAIC filings, published October 13, 2026.

An average depends on the mix of plans behind it. In 2025 the Medigap market leaned heavily on one letter.

Plan F, which can only be bought by people eligible for Medicare before January 1, 2020, still covers millions of older enrollees. Its $325 average is the highest of the major letters, partly because its covered pool can only age. KFF does not publish a national Plan N average. For a focus on the most popular letter, see average Medigap Plan G premium for 2027.

Where you live changes the average more than most people expect. KFF’s state figures for 2025:

KFF, 2025 data. Wisconsin’s Plan G average of $152 is excluded from the low end because Wisconsin uses its own plan designs.

New York shows up at the top partly because it requires community rating and year-round guaranteed issue, so every age pays one price and anyone can buy in at any time. KFF also names Illinois, Indiana and North Dakota just behind Nebraska and New York for Plan F premiums.

KFF states plainly that differences by age, gender or smoking status cannot be evaluated from the data. So no source can honestly give a national average for a 65-year-old woman or a 75-year-old man. Pages that print such figures are usually quoting one insurer, one ZIP code or a sample of quotes.

Converting KFF’s figures into yearly growth rates shows how much the pace picked up recently.

Our calculations from KFF’s 2020, 2024 and 2025 averages (compound annual growth).

Gaps between plan letters also tell a story. The average Plan F holder paid $131 a month, or $1,572 a year, more than the average Plan G holder in 2025. Plan F’s only extra benefit is the Part B deductible, $283 in 2026, so most of that gap reflects an older group of policyholders rather than richer coverage.

Averages describe the market; local rate guides describe your options. Several state regulators have published insurer-by-insurer Medigap rates, including Nevada’s Division of Insurance, Vermont’s Department of Financial Regulation and California’s Department of Insurance through an online tool. Illinois’s Department on Aging has issued regional Medigap premium guides.

For a worked comparison of letters side by side, see Medicare supplement plans cost comparison.