IRMAA in Plain English: The Complete Guide
The stealth Medicare surcharge with a two-year echo, the cliff (not a ramp) that catches Roth converters, and how to appeal it.
The stealth Medicare surcharge with a two-year echo, the cliff (not a ramp) that catches Roth converters, and how to appeal it.
What IRMAA is
Income-Related Monthly Adjustment Amount. If your MAGI from two years ago exceeds certain thresholds, your Medicare Part B and Part D premiums are surcharged for one year — calculated fresh each year from the tax return two years back.
The cliff, not the ramp
IRMAA is a cliff. Cross a threshold by $1 and you pay the entire tier's surcharge for the year. Cross by $50,000 or $1 — same bill. Stop $500 short of the next tier; never cross for a small planning gain.
2026 IRMAA brackets, based on 2024 MAGI — single filer
≤ $109,000: no surcharge (standard Part B $202.90/mo) · $109K–$137K: +$81.20/mo Part B (total $284.10) · $137K–$171K: +$202.90 (total $405.80) · $171K–$205K: +$324.60 (total $527.50) · $205K–$500K: +$446.30 (total $649.20) · > $500K: +$487.00 (total $689.90/mo, or $8,278.80/year). Part D surcharge adds $14.50–$91.00/mo on top of your plan premium, tiered the same way. Source: CMS 2026 Medicare Parts A & B premium announcement.
2026 IRMAA brackets, based on 2024 MAGI — married filing jointly
Thresholds are exactly double the single tiers up to the top: ≤ $218K · $218K–$274K · $274K–$342K · $342K–$410K · $410K–$750K · > $750K. Each spouse on Medicare pays the surcharge separately, so at the top tier the household extra cost is well over $10,000/year.
The two-year lag
Your 2026 premium is based on your 2024 tax return. Your 2027 premium is based on 2025. Every tax move you make before Medicare has a two-year echo. Model it before you pull the trigger.
Common triggers
Roth conversions. Large IRA withdrawals. Selling a rental or business. Big capital gains. Inherited IRA distributions. The one-time event that quietly raises your Medicare cost the following year.
Does tax-free income count?
Muni bond interest is tax-free federally but IS counted in MAGI for IRMAA. Roth withdrawals are NOT counted. This is a key planning distinction.
Per person or per couple?
The threshold is per couple (if filing joint), but the surcharge is per person on Medicare. A married couple over the threshold pays two surcharges.
Life-change appeals
You can appeal for a 'life-changing event' — retirement, divorce, spouse's death, marriage, loss of income-producing property, employer settlement, or loss of pension. File form SSA-44 with documentation. Appeals for 'we just don't like it' don't win.
Does IRMAA go away next year?
Yes — if income drops back below the threshold, the surcharge is recalculated the following year. Not a permanent flag.
The $5,700 conversion mistake
Paul and Nora, both 68, did their own Roth conversion — $80,000 — in December. They hadn't checked their year-to-date income first. Existing MAGI: $205,000. After conversion: $285,000 — crossing the second IRMAA tier ($274K joint under 2026 brackets) by $11,000. Two years later, both paid the tier-2 Part B surcharge ($202.90/mo) plus the Part D surcharge (~$36/mo): about $2,870 per person for the year, ~$5,740 for the couple. The fix that would have worked: convert $68,000 instead of $80,000. Same strategy, stayed under the tier, saved the entire surcharge. The last $12,000 could have gone into the following year.
Every dollar of taxable income in your 60s is also a Medicare-planning decision. The IRMAA information is in your tax return before it's a bill — model MAGI before you press submit.
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