Roth Conversion Tax Calculator
What a conversion actually costs — the correct blended rate, not marginal × amount.
$
$
Extra federal tax$6,600.00Cost of this conversion
Effective rate22.0%Blended across brackets
Room before conversion$41,800.00Before the 22% bracket ends
2026 federal brackets and standard deduction (IRS Rev. Proc. 2025-32, post-OBBBA). Single and married-filing-jointly are modeled; head of household and married-filing-separately are not. Federal income tax only — state tax, IRMAA, NIIT, and the effect on Social Security taxation are not included. The cost shown is the span-integrated effective rate over the converted amount, so a conversion that crosses a bracket is taxed partly at each rate.