2026 retirement tax estimate

Roth Conversion Tax Calculator

Estimate the added federal income tax from a fully pre-tax conversion and compare future tax-rate scenarios. This is an estimate, not individualized tax advice.

Tax year 2026 only

Conversion assumptions

Enter taxable ordinary income after deductions, not salary or AGI. No deduction is subtracted again. This assumes deductions are fully used by other income and stay unchanged; unused deductions are not modeled. State selection identifies your scenario; it does not load state tax law. Supply an effective incremental state/local rate reflecting any applicable exclusions, or zero if appropriate. Verify it separately.

Tax funding and account eligibility

The gross distribution is taxable whether converted or withheld. Withholding reduces the amount reaching Roth. If the 10% additional tax applies, withholding is increased to fund it too. Properly converted amounts themselves are not treated as early distributions here.

Hypothetical retirement comparison

Future rates combine federal and state tax on the traditional account withdrawal. Growth and rates are scenarios, not forecasts. Roth balances assume eventual qualified tax-free withdrawals.

Inputs stay in this browser and are not saved.

How the estimate works

Federal conversion tax is regular ordinary income tax on other taxable income plus the gross distribution, minus tax on other taxable income alone. The 2026 progressive brackets apply by filing status. State/local tax is the gross distribution times your assumed incremental rate. The displayed marginal rates refer to the next dollar before and after conversion, while the effective rate averages tax across the distribution.

With outside funding, the full distribution reaches Roth. The no-conversion alternative keeps the same outside cash available for investment, growing at your after-tax savings rate. With funding from the distribution, Roth receives the gross amount minus withholding; the no-conversion alternative retains the gross amount in the traditional account. With the 10% additional-tax option, withholding = income tax / 0.90, rounded up to cents, so it covers income tax plus the additional tax on withheld funds.

Both retirement accounts use the same growth rate. The traditional balance is reduced by the chosen future combined withdrawal tax rate at comparison; the Roth balance assumes qualified tax-free withdrawal. Break-even is the first whole modeled year, including year 0, when converting equals or exceeds not converting. It is not necessarily a lasting advantage or a recommended conversion date. If neither account has a growth or tax advantage, time alone does not create one.

Scope and exclusions

This model supports fully pre-tax distributions only. After-tax IRA basis and the pro-rata rule require a separate calculation. RMDs cannot be converted. Capital gains, qualified dividends, Social Security taxation changes, AMT, NIIT interactions, deduction phaseouts, credits, Medicare premiums, state-specific rules and fees are excluded. Conversions can affect these even when the bracket estimate looks favorable. Qualified Roth distribution requirements and separate conversion five-year rules still apply. The projection does not model withdrawals before the horizon, RMDs or estate rules.

Annual tax-rule maintenance

Federal brackets: tax year 2026, checked October 2, 2026 against IRS Revenue Procedure 2025-32. Review due December 31, 2026, and before use for any later tax year. This page does not automatically apply these brackets to 2027. State estimates are user assumptions, not a maintained state tax table.

Sources: IRS: 2026 tax rate tables, IRS: IRA conversions, IRS: IRA distributions, Medicare: Income-related premiums, and IRS: Premium tax credit.

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