Standard Tier Module
Medicare IRMAA Part B/D Surcharge Calculator
A deterministic, in-browser tool for senior-care / aging-services advisors (elder-law, senior financial planning, SHIP/benefits counselors) to compute the Medicare Income-Related Monthly Adjustment Amount (IRMAA) on Part B and Part D (42 U.S.C.
Run it on your own figures, 100% in this browser tab
What it is
A deterministic, in-browser tool for senior-care / aging-services advisors (elder-law, senior financial planning, SHIP/benefits counselors) to compute the Medicare Income-Related Monthly Adjustment Amount (IRMAA) on Part B and Part D (42 U.S.C. 1395r(i)). Enter the filing status (single, MFJ, or the separate compressed MFS schedule), the MAGI from the return two years prior (the statutory look-back), and the DATED CMS bracket table - the tool returns the exact tier you land in, the monthly and annual Part B + Part D surcharge, the next threshold, and the "cliff" (one dollar over a threshold jumps a full tier, with no phase-in). No API, no key, no network, no AI - every figure is exact arithmetic over a CITED, year-indexed CMS table. The thresholds and surcharge dollars are DATED inputs you confirm for the IRMAA year; the value actually used is always shown so a wrong year or status never silently mis-computes. Not legal, tax, financial, or benefits advice.
Honest scope
Deterministic and citation-backed: every figure is exact arithmetic or a cited rule. Any year- or jurisdiction-indexed value is a confirmable input, never an eternal hardcode. This is a computation tool, not professional (legal, tax, medical, or financial) advice - confirm against the controlling authority for your context.
Authorities cited
- 42 U.S.C. 1395r(i) - Reduction in premium subsidy based on income (the IRMAA statute): the income-related monthly adjustment amount on the Part B premium.
- 42 U.S.C. 1395r(i)(2)-(3) - The five income tiers and their premium-share percentages (35%, 50%, 65%, 80%, 85% of the unsubsidized premium cost) and, at (i)(3)(C), the separate compressed schedule for married-filing-separately beneficiaries who lived with their spouse.
- 42 U.S.C. 1395r(i)(4) - The "modified adjusted gross income" definition (AGI plus tax-exempt interest) and the use of the return for the year TWO years prior (the look-back year).
- 42 U.S.C. 1395r(i)(5) - Annual inflation indexing of the dollar threshold amounts (so the thresholds shift each year - confirm the CMS notice).
- 42 U.S.C. 1395w-113(a)(7) - The Part D income-related monthly adjustment amount (the Part D IRMAA), mirroring the Part B tiers and applied to the Part D base beneficiary premium.
- CMS, "2025 Medicare Parts A & B Premiums and Deductibles" fact sheet (Nov. 2024) - the 2025 Part B IRMAA dollar amounts and MAGI thresholds (built-in default; confirm the CMS notice for your IRMAA year).
- CMS, 2025 Part D Income-Related Monthly Adjustment Amounts notice - the 2025 Part D IRMAA dollar amounts by tier (built-in default; confirm for your year).
- 20 CFR 418.1101-418.1355 - SSA regulations implementing the Part B income-related premium adjustment, including the MAGI determination and the life-changing-event (SSA-44) reconsideration process.
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Run it on your own data
Open it inside GDBS to save runs to Sandbox, attach results to a Worklog case, or share through a Gate client portal - all in the browser, nothing uploaded to anyone’s cloud.