A Roth conversion increases the income Medicare uses to set IRMAA — the Income-Related Monthly Adjustment Amount added to Part B and Part D premiums — because every converted dollar is taxed as ordinary income. The effect arrives on a delay: Medicare measures income from two years back, so a 2024 conversion shows up in your 2026 premiums.
Revised: 7/24/26
Jason Baar
Fee-Only Medicare Advisor
NPN #2033715
It covers Roth conversions, capital gains, home sales, filing status, and HSAs — with the 2026 bracket lines and worked examples.
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The long answer
The thresholds are what make conversions worth sizing carefully. Surcharges begin once modified adjusted gross income tops $109,000 for a single filer or $218,000 filing jointly, per the Social Security Administration — and each tier is a cliff, so converting one dollar past a line costs the full tier for a year. From about age 63 on, conversion income can raise the premiums you pay in your first years on Medicare.
Know this, too: a Roth conversion is not a qualifying life-changing event, so you cannot appeal the resulting surcharge with form SSA-44. The higher premium simply runs for one year and then resets when a newer return takes over.
None of this means conversions are a mistake. In my fee-only practice, IRMAA is a line item in the conversion math — one year of surcharges is often smaller than the long-term benefit of tax-free growth and smaller future required withdrawals. Run the full comparison before letting a premium veto a conversion.
Printed from JasonKnowsMedicare.com — “Roth Conversions and IRMAA”. The free “Before You Sell the House or Convert That IRA” guide is available at tally.so/r/0QgAAZ · Questions: (850) 810-1000
This page is educational information, not personal financial, tax, or legal advice. For decisions about your own situation, talk with a qualified professional.