Roth Conversion Tax Calculator
Compare conversion amounts and their extra 2026 federal tax, with the blended rate across every bracket they fill.
Reviewed October 25, 2026
Short answer
A conversion is taxed at the blended (span-integrated) rate across the brackets it fills, not your top marginal rate times the amount. Converting $30,000 on $80,000 of single income in 2026 costs $6,600, a flat 22%.
- Within current bracket$30,000.00
- Remaining room in bracket$11,800.00
| Conversion | Extra federal tax | Effective rate |
|---|---|---|
| $0 | $0.00 | 0.00% |
| $15,000 | $3,300.00 | 22.00% |
| $30,000 | $6,600.00 | 22.00% |
| $60,000 | $13,564.00 | 22.61% |
No conversion, half, entered amount, and double (duplicate amounts omitted). Each row subtracts tax without a conversion from tax with that conversion; these are comparisons, not recommended amounts.
This conversion adds approximately $6,600.00 of federal income tax, an effective rate of 22.0% across the converted amount. The next-dollar federal rate before conversion is 22.00%; deduction phaseouts can change that rate within a bracket. This estimate does not include state tax or income-related benefit and premium changes.
Assumes the entire conversion is taxable and uses the standard deduction, age-65 additions and eligible enhanced senior deduction. Excludes IRA basis/pro-rata calculations, itemized deductions, credits, capital gains, AMT, NIIT, state taxes and changes to Social Security taxation. Check Medicare IRMAA and ACA premium tax credits separately. Educational estimate, not tax advice.
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.
This is an educational estimate, not tax or financial advice. Figures reflect the law year shown and the inputs you provide. Consult a qualified professional before acting.
Sources
- Revenue Procedure 2025-32 — Internal Revenue Service
The 2026 federal income-tax brackets and standard deductions.
Accessed September 2, 2026
- Roth IRAs — Internal Revenue Service
Roth IRA contribution, distribution, and conversion tax treatment.
Accessed September 2, 2026
How it’s calculated
- Enter other gross ordinary income before deductions. The calculator subtracts the 2026 standard deduction, age-65 additions and eligible enhanced senior deduction; do not subtract these yourself.
- Add the conversion above it; each dollar is taxed at the bracket it lands in, so a conversion crossing a bracket is taxed partly at each rate.
- Sum the tax across that span and divide by the amount converted for the true effective rate, not marginal × amount.
Worked Roth conversion example
- Other ordinary income
- $80,000
- Conversion
- $30,000
- Filing status
- Single
- Tax year
- 2026
Result
$6,600 of additional federal income tax, a 22% effective rate.
After the standard deduction, this example's conversion remains inside the 22% bracket. A conversion that spans brackets would be split across those rates instead.
What this calculator does not cover
- Assumes a fully taxable conversion. IRA basis/pro-rata calculations, state income tax, capital gains, AMT, NIIT, credits and itemized deductions are not modeled. Standard and eligible senior deductions are included.
- The result does not price IRMAA, ACA premium-tax-credit changes, or additional Social Security taxation.
- Only single and married-filing-jointly statuses are supported.
Frequently asked
- Why isn't it just my tax bracket times the amount?
- Because a large conversion can climb through several brackets. The correct cost integrates the rate across the whole span you convert; your top marginal rate overstates it, and your current bracket alone understates it.
- What does this calculator leave out?
- Federal income tax only, single or married-filing-jointly. This calculator does not model state tax, Medicare IRMAA, NIIT, or how the added income changes Social Security taxation. The full Meridary planner also models a flat state tax rate, Social Security taxation, Medicare IRMAA, and ACA premium tax credits within its stated assumptions. NIIT remains out of scope.
Related reading
Explore more worked examples on the retirement planning blog.