Roth IRA Conversion Tax Calculator
Converting a traditional IRA to a Roth means paying income tax on the amount converted today, in exchange for tax-free withdrawals later. This calculator estimates the federal tax cost of your conversion using the 2026 tax brackets.
How this calculator works
The calculator applies the 2026 federal income tax brackets to your income before and after the conversion. The difference between the two tax totals is the estimated tax owed on the converted amount. Because conversions are added on top of your regular income, they are taxed at your marginal rate — which is why many people convert in low-income years. State taxes are not included, and the pro-rata rule may change the picture if you also hold pre-tax money in a traditional IRA.
Frequently asked questions
When does a Roth IRA conversion make sense?
A conversion is most attractive in a year when your taxable income is unusually low — for example, between jobs, during a sabbatical, or in early retirement. Paying tax at a low marginal rate now can save far more later if your withdrawals would otherwise fall in a higher bracket.
What is the pro-rata rule?
If you have any pre-tax money in traditional IRAs (including rollovers from old 401(k)s), a conversion is taxed proportionally based on the ratio of pre-tax to after-tax money across all your traditional IRAs — not just the account you convert. This can make a conversion more expensive than expected.
Can I undo a Roth conversion?
Recharacterization — reversing a conversion — was eliminated for conversions made after 2017. Once you convert, the money stays in the Roth, though you can always withdraw your contributions (not earnings) tax-free at any time.
Disclaimer: Results are estimates for general information only and do not constitute financial, tax, or legal advice. Figures reflect 2026 rules and may change. Always confirm current limits and consult a qualified professional before making decisions. Official figures: IRS.gov · 2026 limits per IRS tax inflation adjustments.