Roth Check

How this works. Federal tax uses the 2026 brackets and standard deductions from IRS Revenue Procedure 2025-32 (married filing jointly $32,200, single $16,100). A conversion is added to this year's income and fills the tax layers from the bottom up. The Medicare surcharge (IRMAA) lines are $218,000, $274,000, $342,000 and $410,000 for a married couple and $109,000, $137,000, $171,000 and $205,000 for a single filer, based on income from two years earlier; the Part B surcharge is about $81.20, $202.90 and $324.60 a month per person for the first three steps, and higher above the fourth line. The later-rate view taxes your retirement income with the Social Security rules (part of the benefit is taxable once other income passes $32,000 married or $25,000 single, thresholds that are not adjusted for inflation) and assumes the required withdrawal at 75 uses the IRS divisor of 24.6 with no growth. Left out on purpose: state income tax, inflation, investment returns, and the extra deductions available at 65 and over, which would make later taxes lower still. A conversion cannot be undone, and some 401(k) plans do not allow conversions inside the plan. This is general information, not financial or tax advice. Ask a tax professional before you convert.