How much tax will a Roth conversion cost me?

A Roth conversion is taxed as ordinary income stacked on top of your existing income. For example, a single filer with $90,000 taxable income converting $50,000 pays about $11,733 in extra federal tax, an effective conversion rate of roughly 23.5%.

Will a conversion push me into a higher tax bracket?

It can. The conversion adds to your taxable income, so part of it may be taxed at a higher marginal rate. In the example above, $90,000 of income sits in the 22% bracket, but the conversion pushes the top of the stack into the 24% bracket at $140,000.

Is the whole conversion taxed at my top rate?

No. Only the portion that crosses into a higher bracket is taxed at that higher rate. That is why the effective conversion rate (23.5% in the example) sits between the 22% and 24% marginal rates rather than at a single flat number.

Does this include state tax?

No. This tool estimates only federal income tax on the conversion. State income tax, Medicare IRMAA surcharges, and the 3.8% net investment income tax are separate and can add meaningfully to the total cost.

Roth IRA Conversion Calculator

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Converting traditional IRA money to a Roth IRA means paying income tax now in exchange for tax-free growth and withdrawals later. This calculator stacks the conversion on top of your 2026 taxable income, applies the federal brackets, and shows the extra tax, your new marginal bracket, and the effective rate on the conversion.

How it works

A Roth conversion counts as ordinary income in the year you convert. The tool computes your tax twice using the 2026 progressive brackets and takes the difference:

conversionTax = tax(income + conversion) − tax(income)
effectiveRate = conversionTax / conversion

Because the brackets are progressive, only the part of the conversion that crosses a bracket boundary is taxed at the higher rate. Your input is treated as taxable income already (after the standard deduction), so the deduction is not applied again.

Example

A single filer has 90,000 dollars of taxable income and converts 50,000 dollars. Tax on 90,000 is about 14,714 dollars. Adding the conversion brings taxable income to 140,000 dollars, where the tax is about 26,447 dollars.

conversionTax = 26,447 − 14,714 = 11,733
effectiveRate = 11,733 / 50,000 = 23.47%

The conversion pushes the top of the stack from the 22% bracket into the 24% bracket, so the new marginal rate is 24%.

Notes

Estimate only, not tax or financial advice. The calculator covers federal income tax using the 2026 brackets and treats the input as taxable income. It does not model state tax, Medicare IRMAA surcharges, the 3.8% net investment income tax, or pro-rata rules for after-tax IRA basis. Confirm your plan with a tax professional or at irs.gov.