How IRMAA works, in 30 seconds
IRMAA (income-related monthly adjustment amount) is a surcharge on Medicare Part B and Part D for people with higher incomes. Medicare looks at your tax return from two years earlier, so 2027 premiums are set by 2025 income.
It is a cliff, not a phase-in. One dollar over a line moves you into the next tier for the whole year, and on a joint return both spouses on Medicare pay it. The first 2027 line is projected at $112,000 single and $224,000 joint, up from the official 2026 lines of $109,000 and $218,000 (CMS, 2026). The standard Part B premium is projected at $209.50 a month for 2027 (2026 Medicare Trustees Report), up from the official $202.90 in 2026.
The official 2027 figures are not announced yet. CMS usually publishes them in mid November. Until then every 2027 number on this page is a projection, made October 4, 2026 from the 2026 Medicare Trustees Report and federal inflation data (CPI-U through August 2026). See the 2026 premiums and brackets, the IRMAA calculator and how people avoid IRMAA.
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