How is modified adjusted gross income (MAGI) defined for Medicare premium purposes in 2025?
Executive summary
For Medicare premium (IRMAA) purposes in 2025, “MAGI” is the modified adjusted gross income reported on your most recently filed federal tax return from two years earlier — i.e., 2023 MAGI determines 2025 surcharges — and it typically equals your AGI plus tax-exempt interest and certain other items depending on the tax-code definition used by CMS and SSA (see sources) [1] [2] [3].
1. How Medicare uses MAGI: surcharge trigger and timing
Medicare’s Income-Related Monthly Adjustment Amount (IRMAA) for Parts B and D is based on your MAGI from two years prior; for 2025 premiums administrators look at your 2023 tax return to determine whether you pay higher premiums in 2025 [4] [5]. Multiple consumer and advisory outlets reiterate that the Social Security Administration (which administers IRMAA determinations) relies on the most recently filed federal return, so the relevant year is the tax return filed two years earlier for the premium year [6] [7].
2. What “MAGI” means in practice for IRMAA calculations
Practical guides and calculators used by financial-planning outlets explain the MAGI used for IRMAA as essentially your adjusted gross income (AGI) plus tax-exempt interest (for example, muni-bond interest) and sometimes other items that differ across definitions of MAGI; for IRMAA the items added to AGI include tax‑exempt interest and certain municipal bond dividends, so your MAGI can exceed AGI [2] [3]. Sources caution there are several official definitions of MAGI used across programs (ACA, Medicaid, Medicare), so the exact components can vary by context [6] [8].
3. Income thresholds and how they map to MAGI
Advisory publications summarize the threshold effect: for 2025, IRMAA surcharges apply when modified AGI from 2023 exceeds specified cutoffs (single filers over $106,000; joint filers over $212,000 are the starting thresholds widely cited), and higher brackets produce larger surcharges for Parts B and D [1] [6]. Detailed bracket charts and dollar amounts are published by commentary sources and were updated in late‑2025 materials, but the consistent point across reporting is that the SSA/CMS process uses the MAGI reported on the relevant filed return [9] [1].
4. Common sources of confusion — different MAGI definitions
Journalists, tax pros and government glossaries highlight that “MAGI” is not a single universal figure: the ACA/Medicaid MAGI definition explicitly lists AGI plus untaxed foreign income, non‑taxable Social Security and tax‑exempt interest — but reporting for IRMAA focuses on tax return figures like AGI plus tax‑exempt interest and certain exclusions, so readers must not assume every MAGI definition is identical [3] [8]. Experts warn that statements conflating the various program definitions (for example, including untaxed Social Security in IRMAA MAGI) are sometimes incorrect for Medicare purposes [2].
5. Planning implications and disputed details
Tax and financial‑planning outlets emphasize that events raising taxable income (Roth conversions, large IRA distributions, sale of a business, taxable inheritances) can increase MAGI for the relevant year and therefore raise IRMAA for the premium year two years later; these outlets recommend planning to smooth income or use qualifying life‑change events to request adjustments when appropriate [4] [10]. However, precise inclusions (e.g., whether certain non‑taxable items are counted) vary by which MAGI definition commentators reference, so practitioners and beneficiaries should confirm which items SSA/CMS will count in IRMAA determinations rather than relying on generalized MAGI descriptions [2] [3].
6. Where to get the authoritative number and next steps
Sources point beneficiaries to the Social Security Administration and CMS notices for final IRMAA brackets and to one’s filed federal tax return for the MAGI value used; planning articles reiterate that the SSA looks at the most recently filed return [7] [1]. Available sources do not mention a single, consolidated government plain‑language checklist in these excerpts that lists every item included or excluded from IRMAA MAGI; beneficiaries should consult SSA/CMS guidance or a tax professional for definitive treatment of specific income items (not found in current reporting).
Limitations: this analysis synthesizes reporting and consumer guidance in the provided sources; exact line‑by‑line treatment of every income item for IRMAA is not exhaustively listed in these excerpts and different MAGI definitions exist across programs [3] [2].