Roth Conversion Calculator

Background.

A reader arrives at Roth Conversion Calculator to estimate current tax on the taxable portion of a traditional-account conversion. A Roth conversion moves pretax IRA value into Roth status and generally includes untaxed amounts in current income. For that reason, this page names its convention as “estimated conversion tax = conversion amount × taxable percentage × entered marginal tax rate.”

The editable entries are traditional-account amount converted, taxable percentage of conversion, marginal income-tax rate, external cash available for conversion tax. Use values from the document or measurement that governs this roth conversion question; the defaults are only the worked fixture below. Before relying on the number, check this roth conversion boundary: the conversion can cross brackets, affect credits and Medicare premiums, and cannot be characterized by one marginal rate alone.

IRS Publication 590-A, Contributions to Individual Retirement Arrangements; IRA contribution and conversion basis rules documents the convention or governing rule used here. The roth conversion output is a transparent scenario under those facts: it does not manufacture an unentered market price, professional determination, carrier quote, legal eligibility finding or locally adopted code value.

What is roth conversion calculator?

Roth Conversion is the relationship behind this decision: a Roth conversion moves pretax IRA value into Roth status and generally includes untaxed amounts in current income. On this page it means estimated conversion tax = conversion amount × taxable percentage × entered marginal tax rate. The conversion can cross brackets, affect credits and Medicare premiums, and cannot be characterized by one marginal rate alone; that is the line between the reported quantity and a broader retirement analysis.

How to use this calculator.

1. 01Confirm that “estimated conversion tax = conversion amount × taxable percentage × entered marginal tax rate” matches the roth conversion convention you need.
2. 02Replace the fixture values for traditional-account amount converted, taxable percentage of conversion, marginal income-tax rate, external cash available for conversion tax with dated values from the governing record.
3. 03Keep all currencies, measurement units and time periods on the same basis before calculating.
4. 04Read estimated income tax on conversion together with this boundary: The conversion can cross brackets, affect credits and Medicare premiums, and cannot be characterized by one marginal rate alone.

The formula.

The calculation uses estimated conversion tax = conversion amount × taxable percentage × entered marginal tax rate. In this roth conversion model, the entered terms are traditional-account amount converted, taxable percentage of conversion, marginal income-tax rate, external cash available for conversion tax. A Roth conversion moves pretax IRA value into Roth status and generally includes untaxed amounts in current income, which is why the relationship is presented under this name rather than as a universal alternative. The conversion can cross brackets, affect credits and Medicare premiums, and cannot be characterized by one marginal rate alone. Calculations keep full decimal precision through the relationship and round only the returned display values.

A worked example.

Frequently asked questions.

References& sources.

1. [1]IRS Publication 590-A, Contributions to Individual Retirement Arrangements; IRA contribution and conversion basis rules. Retrieved 2026-08-07. access: open unless marked otherwise.
2. [2]U.S. Internal Revenue Service. About Form 8606, Nondeductible IRAs. Retrieved 2026-08-07. independence: primary; access: open.
3. [3]U.S. Internal Revenue Service. Publication 590-B, Distributions from Individual Retirement Arrangements. Retrieved 2026-08-07. independence: primary; access: open.
4. [4]U.S. Internal Revenue Service. Tax inflation adjustments for tax year 2026. Retrieved 2026-08-07. independence: primary; access: open.
5. [5]U.S. Internal Revenue Service. Instructions for Form 8606, Nondeductible IRAs. Retrieved 2026-08-07. independence: primary; access: open.