Calculation Methodology
Federal tax is estimated with a progressive tax delta: tax(income + taxable conversion) minus tax(income).
Taxable conversion uses a pro-rata basis estimate: conversion amount multiplied by one minus basis divided by IRA balance.
The default assumption is that conversion taxes are paid from outside funds.
IRMAA, ACA APTC, NIIT, Social Security, RMD, AMT, and selected-state inputs may appear as bounded previews or professional-review worksheets, but final program eligibility, tax forms, credits, billing determinations, and state-specific rules remain outside the core conversion tax calculation.
Primary references: IRS Publication 590-A, IRS Publication 590-B, and IRS tax inflation adjustments for tax year 2026.
Tax data freshness
Tax year 2026, updated May 30, 2026. Federal calculations are educational estimates based on the inputs provided by the user.
Tax professional review pending; use this as an educational estimate only.
Source basis: IRS annual tax inflation adjustments and retirement account publications. Updated within 15 business days after new annual IRS tax tables are released.
Not modeled: final IRMAA billing determinations, ACA subsidies, NIIT final Form 8960 calculations, AMT, tax credits, state-specific deductions.
Review the tax data update playbook2026 Federal Tax Brackets Used
The calculator uses a progressive tax delta method. These brackets are included so users can verify the tax-year assumptions.
Single
| From | To | Rate |
|---|---|---|
| $0 | $12,400 | 10% |
| $12,400 | $50,400 | 12% |
| $50,400 | $105,700 | 22% |
| $105,700 | $201,775 | 24% |
| $201,775 | $256,225 | 32% |
| $256,225 | $640,600 | 35% |
| $640,600 | No limit | 37% |
Married filing jointly
| From | To | Rate |
|---|---|---|
| $0 | $24,800 | 10% |
| $24,800 | $100,800 | 12% |
| $100,800 | $211,400 | 22% |
| $211,400 | $403,550 | 24% |
| $403,550 | $512,450 | 32% |
| $512,450 | $768,700 | 35% |
| $768,700 | No limit | 37% |
Married filing separately
| From | To | Rate |
|---|---|---|
| $0 | $12,400 | 10% |
| $12,400 | $50,400 | 12% |
| $50,400 | $105,700 | 22% |
| $105,700 | $201,775 | 24% |
| $201,775 | $256,225 | 32% |
| $256,225 | $384,350 | 35% |
| $384,350 | No limit | 37% |
Head of household
| From | To | Rate |
|---|---|---|
| $0 | $17,700 | 10% |
| $17,700 | $67,450 | 12% |
| $67,450 | $105,700 | 22% |
| $105,700 | $201,750 | 24% |
| $201,750 | $256,200 | 32% |
| $256,200 | $640,600 | 35% |
| $640,600 | No limit | 37% |
Related Roth conversion references
Use these companion pages to trace the calculator inputs, bracket data, example scenarios, and professional review handoff without treating the estimate as personal tax advice.