How much ordinary federal tax does a Roth conversion add, and how much bracket room remains?

Estimate a traditional IRA conversion's ordinary federal income tax using aggregate IRA basis, projected year-end values, other distributions, and deductions that remain fixed. Compare the proposed conversion with the gross amount that fits below a chosen bracket ceiling. This is not a complete tax-return projection: preferential income and income-sensitive interactions are blocked.

Includes other IRA distributions at their taxable amount. All income must be ordinary-rate income.

Enter the selected year's deduction yourself, including age/blind additions. Income-sensitive deductions are unsupported.

Aggregate this owner's traditional, SEP and SIMPLE IRAs. Exclude employer plans and inherited IRAs.

Form 8606 basis available to distributions; exclude contributions made next calendar year.

Tax-free rollovers, corrections, recharacterizations, and outstanding rollovers are unsupported.

RMD dollars cannot be converted.

Select for gains, qualified dividends, Social Security, AMT, QBI, senior-deduction phaseouts, credits, or ACA subsidy changes. These block this ordinary-tax estimate.

roth conversion calculator

Quick answer

Estimate a traditional IRA conversion's ordinary federal income tax using aggregate IRA basis, projected year-end values, other distributions, and deductions that remain fixed. Compare the proposed conversion with the gross amount that fits below a chosen bracket ceiling. This is not a complete tax-return projection: preferential income and income-sensitive interactions are blocked.

Also answers

  • Roth conversion tax calculator
  • Roth conversion bracket room
  • IRA conversion pro rata basis
  • tax before and after Roth conversion

Good fit when

  • Ordinary-income federal bracket planning without phaseout interactions
  • Understanding conversion basis allocation
  • Comparing a proposed conversion with available bracket room

Have ready

  • Tax year, filing status and chosen top bracket
  • Ordinary income and independently verified fixed deductions
  • Gross conversion, basis and aggregate post-conversion year-end values
  • Other distributions and confirmation of supported tax scope

Result you get

Taxable and basis conversion portions, ordinary tax before/after, incremental tax, taxable room and gross conversion ceiling.

backdoor roth helpermedicare irmaa calculatorira contribution eligibility calculator2027 published amounts and planning status

How this calculation works

  • Allocate basis using aggregate year-end IRA values plus conversions and other distributions, excluding unsupported special transactions.
  • Compute ordinary taxable income before and after conversion using the same entered fixed deduction.
  • Calculate progressive ordinary tax for the selected filing status and subtract the pre-conversion tax.
  • Solve bracket room using the taxable fraction and remaining fixed deductions; cap gross room at convertible IRA balances.
  • Unpublished 2027 indexed numbers use explicitly labeled 2026 provisional baselines, never an official 2027 forecast.
  • Default 2026 example: $50,000 ordinary AGI, $16,100 fixed deductions and a $25,000 all-taxable conversion add $3,850 of ordinary federal tax.

Common mistakes and caveats

  • Not a complete Form 8606 or tax return: outstanding rollovers, contribution corrections, recharacterizations, inherited IRAs, and annuities are unsupported.
  • Confirm a SIMPLE IRA conversion is eligible, including any applicable initial participation restrictions.
  • No state income tax, AMT, NIIT, credit changes, Social Security inclusion, subsidy loss, withholding penalty, or future Medicare premiums.
  • RMDs cannot be converted; the form requires current RMD satisfaction or confirmation that none is due.

FAQ

Is a Roth conversion limited by the annual IRA contribution cap?

No. An eligible conversion is a retirement-account transfer, not a new annual contribution. The Roth contribution MAGI ceiling does not itself prohibit a conversion. Account eligibility, RMDs, distribution rules, and conversion reporting still matter. This tool models a completed eligible conversion with any current RMD already satisfied, not whether every transfer qualifies.

Why do all my traditional, SEP and SIMPLE IRAs matter?

Form 8606 generally pools the owner's IRA basis and balances when allocating the taxable and nontaxable portions. You cannot select only a basis-heavy account to avoid the pro-rata rule. The entered December 31 total is after the proposed conversion; conversions and other distributions are added back into the denominator. Employer plans and inherited IRAs are not pooled here.

What does maximum gross conversion at the target bracket mean?

It is the amount of available IRA resources that can be shifted from year-end balances into a conversion without exceeding the chosen ordinary taxable-income ceiling under the supplied assumptions. The aggregate resources and basis ratio remain fixed in that comparison. It is capped by convertible balances, and does not mean the conversion is optimal after every tax or benefit interaction.

What happens when deductions exceed my ordinary income?

Unused fixed deductions can absorb part of the taxable conversion before ordinary taxable income becomes positive. The engine retains that unused deduction space rather than treating a zero-taxable-income starting point as though every conversion dollar immediately enters a tax bracket. Deductions that phase out as income rises cannot be entered as fixed without a separate projection.

Can this include Social Security, senior deductions or capital gains?

No. Select the interaction checkbox to block the simplified estimate when preferential gains, qualified dividends, Social Security taxation, AMT, QBI, income-sensitive senior deductions, credits, or ACA subsidies apply. These can change the incremental tax materially. Medicare IRMAA and state tax are separate consequences, not additions silently included in the federal bracket calculation.

Is the 2027 bracket result official?

No. Until the IRS publishes 2027 indexed brackets, the 2027 option explicitly uses the verified 2026 brackets as a provisional baseline. The user-entered deduction must independently match the intended scenario. Historical 2025 calculations keep their published 2025 brackets. Dollar results use progressive-rate arithmetic rather than the rounded IRS Tax Table.

Last updated & sources

Last updated October 13, 2026.

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