Method & sources

Every number on this site traces to one of the sources below. There is a single data file behind all pages, so when CMS publishes the official figures, the whole site updates in one pass — no page can quietly keep a stale number.

Where each 2027 number comes from

Income thresholds (the brackets)

Federal law — 42 U.S.C. §1395r(i)(5) — sets the formula: each threshold is its statutory base amount, raised by the growth in the average CPI-U (all items, not seasonally adjusted, BLS series CUUR0000SA0) for the twelve months ending the August before the premium year, then rounded. We compute the thresholds from that formula. The identical computation reproduces the official CMS thresholds for 2024, 2025 and 2026 to the dollar, which is why we publish the 2027 result as a calculation rather than a guess.

One wrinkle: the October 2025 CPI was never published because of the federal government shutdown, so the twelve-month average contains eleven prints. Treating the missing month two reasonable ways moves three middle thresholds by $1,000 (single) or $2,000 (joint). We use the lower value and flag the alternative everywhere it appears; CMS will settle it in its announcement.

Part B premium amounts

The standard premium shown is the 2026 Medicare Trustees Report projection, $209.50. Each higher tier is fixed by law as a share of total Part B cost — 35%, 50%, 65%, 80% or 85% in place of the standard 25% — so the tier premiums follow from the standard premium by arithmetic (for example, Tier 1 = $209.50 × 35 ÷ 25 = $293.30). When CMS announces the official standard premium, every tier moves in proportion.

Part D add-ons

These are computed under 42 U.S.C. §1395w-113(a)(7) from the 2027 base beneficiary premium of $41.33, which CMS published on July 28, 2026 — that input is official. The same computation reproduces the official Part D amounts for 2022–2026.

2025 and 2026 figures

Official, from the CMS fact sheets "2025 Medicare Parts A & B Premiums and Deductibles" (November 8, 2024) and the 2026 edition (November 14, 2025).

What happens on announcement day

CMS publishes a fact sheet titled "2027 Medicare Parts A & B Premiums and Deductibles" in its newsroom, usually in mid-November. We check the CMS newsroom daily during the window. When it lands, we replace the projected premium with the official figure, confirm the thresholds against the published table digit by digit, flip every "projected" label on the site, and note the change here. Until then, nothing on this site presents a projection as an official figure.

Limits

This site explains published law and arithmetic. It is not tax, legal, or financial advice, and it is not affiliated with CMS, Medicare.gov, or the Social Security Administration — they decide your actual premium, and you can confirm it at Medicare.gov or in the notice Social Security mails you each fall.

Status of this page: checked November 13, 2026. CMS had not yet published the 2027 fact sheet.