Is IRMAA calculated every year?
Yes, in two separate ways. Social Security sets your surcharge fresh for every premium year, working from the newest filing the IRS can hand over, generally two years old and never more than three, so 2026 premiums rest on 2024 MAGI. The income lines that trigger the surcharge also move annually with inflation: the first threshold sat above $106,000 single and $212,000 joint for 2025 and sits above $109,000 and $218,000 for 2026, while the top tier stays frozen at $500,000 and $750,000 until 2028. Because every year stands alone, an expensive tax year affects a single premium year; how long a surcharge runs before it drops off has its own page.
How does Social Security recalculate IRMAA each year?
Automatically. You file nothing and request nothing; "calculated" and "recalculated" describe the same machinery, one annual redetermination. Each fall SSA matches the newest IRS data against the coming year's tiers and mails the result: the annual notice arrives in November, ahead of the January change. A different letter, the Initial IRMAA Determination, can show up in any month, typically when someone first enrolls or when the IRS transmits updated figures.
A quirk hides in the three-year backstop. IRS data can run late, and when it does, SSA decides from the three-year-old return instead. Handing SSA the newer return once it exists gets the decision corrected (POMS HI 01120.001); no life event is required for that fix.
Do the IRMAA brackets change every year too?
Yes, by statute. The law fixes a set of base thresholds and ties them to inflation: each year's tiers scale the base by CPI-U growth, measured over the 12 months that close in August, with the result rounded to the nearest $1,000 (42 U.S.C. §1395r(i)(5)). The exception is the top tier, held until 2028 at $500,000 for singles and $750,000 for joint filers. The movement is visible across just two years:
| Premium year | Return SSA reads | Tier 1 begins, single filer | Tier 1 begins, joint | Part B standard premium |
|---|---|---|---|---|
| 2025 | 2023 | above $106,000 | above $212,000 | $185.00 |
| 2026 | 2024 | above $109,000 | above $218,000 | $202.90 |
Source: CMS fact sheets, announced November 8, 2024 (2025) and November 14, 2025 (2026).
That was a $3,000 climb in the single first threshold and $6,000 in the joint one, in a single year. Feeding the CPI readings published so far through the same formula yields the 2027 bracket projections.
When does the new amount take effect?
January 1, and it holds through December. CMS publishes the next year's figures first, in recent practice in November: November 14, 2025 for the 2026 numbers, November 8, 2024 for 2025. SSA's letter follows the same month, and the premium itself changes with the new year. The IRMAA calculator places any 2024 MAGI in its 2026 tier, and every 2026 table, single through separate, is on the 2026 IRMAA brackets page.
What if the recalculation uses wrong or outdated income?
SSA will redo the decision when the inputs were wrong. An IRS transmission error, an amended return, or a newer return than the one SSA used each supports a new determination; the IRMAA appeal guide sets out the evidence for each ground. Income that has genuinely fallen since the return, through retirement or some other qualifying event, takes a different route: Form SSA-44 along with your estimated MAGI for the reduced year.
The annual redetermination rule comes from SSA POMS HI 01101.010 and HI 01120.001, the indexing formula from 42 U.S.C. §1395r(i)(5), and the premium figures from the CMS announcements dated above.