Roth Conversion Calculator — 2026 (federal, with IRMAA & senior-deduction effects)
🔒 100% client-side — nothing is uploaded, ever
Tables: IRS Rev. Proc. 2025-32 · CMS 2026 IRMAA (Nov 14, 2025) · OBBBA §70103
Updated Nov 2026
Filer
Filing status
Married filing jointly
Single
Married filing separately
Lived with spouse at any time during 2026 (affects §86 & IRMAA)
You are 65 or older (this year)
Spouse is 65 or older
Enrolled in a Part D drug plan
Existing 2026 income
Wages / pension / other ordinary
Interest & ordinary dividends
Qual. dividends + net LTCG
Tax-exempt (municipal) interest
Social Security — you
Social Security — spouse
Traditional IRA & conversion
Pre-tax IRA / 401(k) balance you could convert
Non-deductible basis (Form 8606)
Roth conversion amount for 2026:
$20,000
Amounts in USD. RMD for the year (age 73+) must be taken before converting. §408A pro-rata applies automatically if you have basis.
v1: standard deduction only; state tax, AMT, QBI ignored.
Extra federal tax
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Extra Medicare premium / yr
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Extra NIIT
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All-in cost per $1 converted
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Cost curve — the "cliff map"
(all-in cost of converting $X more)
Assumptions & exact numbers used (for your review)
Self-test (dev): spec test vectors