2026 tax calculator
A Roth conversion, bracket by bracket.
See the incremental federal ordinary-income tax and optional Medicare IRMAA tier exposure created by a proposed Roth conversion.
Educational estimate — not tax advice. This is a narrow 2026 federal bracket illustration, not a recommendation to convert.
Assumptions used
Deductions start at the official 2026 base standard deduction, remain adjustable, and reset to the matching amount when filing status changes.
Filing status
Married Filing Separately is not modeled.
Federal ordinary income before subtracting the deductions entered below.
Allowed range: 0 to 10000000.
Amount moved from a pre-tax retirement account and treated here as ordinary income.
Allowed range: 0 to 10000000.
Subtracted once from ordinary income. Adjust only if a different deduction amount applies to your illustration.
Allowed range: 0 to 10000000.
Medicare IRMAA estimate
Turn on a separate estimate of 2026 Medicare Part B and Part D income-related adjustments.
For IRMAA only: adjusted gross income plus tax-exempt interest before this conversion. It is not reduced by the deduction above.
Allowed range: 0 to 10000000.
- Filing status
- Single
- Ordinary income
- $100,000 before deductions
- Deductions applied once
- $16,100
- Taxable income before conversion
- $83,900
- Proposed conversion
- $50,000
- Taxable income after conversion
- $133,900
Caution
Incremental federal tax
$11,564
$24,734 after minus $13,170 before.
Caution
Effective tax rate on conversion
23.13%
Incremental federal tax divided by the proposed conversion; 0% when conversion is $0.
Positive result
Marginal bracket: before → after
22% → 24%
Marginal ordinary-income rate immediately before and after the proposed conversion.
Positive result
Room in bracket before conversion
$21,800
After conversion: $67,875 remains in the 24% bracket.
Positive result
Conversion sheltered by unused deductions
$0
The portion covered by deductions that exceed ordinary income, modeled at 0% before taxable brackets begin.
Where the conversion lands
Each bar starts after dollars sheltered by unused deductions or assigned to lower tax brackets, creating a complete waterfall. The table is the text alternative and reconciles to the proposed conversion and incremental tax above.
| Tax treatment | Basis or 2026 taxable-income range | Conversion dollars | Estimated tax |
|---|---|---|---|
| 22% | Over $50,400 through $105,700 | $21,800 | $4,796 |
| 24% | Over $105,700 through $201,775 | $28,200 | $6,768 |
Medicare IRMAA is off. Turn it on to compare separate before-and-after 2026 tiers and annual Part B plus Part D adjustments per enrollee.
Method and limits
Taxable income before = max(0, ordinary income − deductions). Taxable income after = max(0, ordinary income + conversion − deductions). Any unused deductions shelter conversion dollars before the remaining amount fills the 2026 ordinary-income brackets. Federal tax is calculated before and after without intermediate rounding.
State tax, capital-gains stacking, NIIT, ACA subsidies, Social Security taxation, future growth, age or blindness additions, dependents, itemization rules, and Married Filing Separately are excluded. This calculator does not provide individualized tax advice or a conversion recommendation.
Each published threshold is the inclusive upper edge of its bracket. Income equal to the threshold remains in that bracket; only the next dollar begins filling the next rate. The allocation table follows that boundary rule exactly.
Official 2026 sources
Rates, deductions, thresholds, and adjustments verified 2026-08-11.
Educational use only — not tax advice. A Roth conversion can affect taxes and benefits outside this narrow model. Consult a qualified tax professional about your facts before acting.
Share this view
Copy the prepared link. Nothing is shared until you choose to send it.
Copy this code into a page that accepts HTML embeds.
Ordinary edits remain local to this browser session. Inputs enter a URL only when you choose to copy the share link or embed code.
Questions this model answers
What tax does this Roth conversion calculator estimate?
It estimates only the incremental 2026 federal ordinary-income tax created by the entered conversion under the Single or Married Filing Jointly bracket schedule.
How are deductions handled?
The entered deductions are applied once to ordinary income plus the conversion. If deductions exceed ordinary income, the unused amount can shelter part of the conversion at 0% in this estimate.
How does the Medicare IRMAA estimate work?
It adds the proposed conversion to the separately entered IRMAA MAGI, selects the official 2026 before and after tiers, and annualizes the Part B and Part D income-related adjustments per Medicare enrollee.
Is this tax advice or a complete Roth conversion analysis?
No. It is an educational bracket illustration, not tax advice. It excludes state tax, capital-gains stacking, NIIT, ACA subsidies, Social Security taxation, future growth, and other individualized circumstances.