What does this Roth conversion calculator estimate?
This calculator multiplies a taxable conversion amount you enter by two marginal rates you choose. For example, its editable defaults apply 22% and 24% to a hypothetical $10,000 taxable amount, producing simple amounts of $2,200 and $2,400. These numbers only demonstrate the arithmetic; they are not IRS rates, a forecast, or a claim about a typical taxpayer. The difference between the two results shows how the selected rate changes this simplified calculation.
Use the taxable portion, not automatically the full amount moved to a Roth IRA. The IRS explains that a conversion can make previously untaxed traditional IRA amounts taxable in the year of conversion, and Form 8606 is used to report conversions and nondeductible IRA basis. The taxable portion depends on your records and facts. This tool does not derive it from the total converted, account balance, or basis.
Why can the pro-rata calculation matter?
Having nondeductible contributions does not by itself mean a conversion is tax-free. Form 8606 uses a calculation to account for basis and other IRA amounts; depending on your situation, the nontaxable share may not equal the particular dollars you identify as nondeductible. The form instructions include year-end account-balance and distribution information in the computation. Review the current form and instructions, including relevant traditional, SEP, or SIMPLE IRA records, before entering a taxable amount. This page does not perform the pro-rata calculation or determine which records apply.
Why is the estimated tax only a scenario?
The calculator applies one rate to the entire taxable amount. Actual federal income tax uses your full tax return and may involve more than one marginal bracket when added income crosses a bracket threshold. The result also omits filing status, other income, deductions, credits, withholding, state and local taxes, and other tax provisions. The user-entered rate is an assumption, not a rate looked up or validated by this site.
A conversion decision can involve tax timing, available funds to pay tax, and account-specific rules beyond this calculation. Check current IRS materials and consult a qualified tax professional for advice about your circumstances. The IRS notes that untaxed amounts converted to a Roth IRA are generally included in income for the conversion year. This educational page does not recommend converting or not converting and is not tax, legal, or investment advice.
Frequently asked questions
Does this calculator determine the taxable part of my conversion?
No. Enter a taxable amount you have determined from your records and applicable rules. IRS Form 8606 may be needed to account for basis and other IRA amounts.
Why can the pro-rata calculation matter?
Nondeductible basis does not automatically make a conversion tax-free. Form 8606 uses a calculation that can include year-end IRA balances and distributions, so the taxable portion may differ from the amount converted.
Does this estimate my full tax bill or recommend a conversion?
No. It multiplies one amount by two rates you enter. It does not model tax brackets, other income, deductions, credits, state taxes, or future account outcomes, and it gives no conversion recommendation.
Where can I check the rules?
See the IRS IRA FAQs, Form 8606 information, and current Form 8606 instructions.
Primary sources checked 2026-11-03: IRS Retirement Plans FAQs Regarding IRAs; About Form 8606, Nondeductible IRAs; Instructions for Form 8606 (2025). IRS sources support the discussion of conversion income and Form 8606; they do not supply or validate the scenario rates.