Roth Conversion Tax Calculator
Converting a Traditional IRA to a Roth IRA triggers ordinary income tax on the converted amount in the year of conversion. Smart Roth conversion planning often involves converting just enough each year to "fill up" your current tax bracket without pushing income into the next one. This calculator shows the federal income tax on a proposed conversion amount given your existing taxable income, and also shows how much additional conversion you could do while remaining in your current bracket.
Roth conversion tax formula
Total income = other income + conversion amount
Tax on total = apply 2025 progressive brackets to total income
Tax on other income = apply 2025 progressive brackets to other income
Tax on conversion = Tax on total - Tax on other income
2025 single brackets: 10% up to $11,925; 12% up to $48,475; 22% up to $103,350; 24% up to $197,300; 32% up to $250,525; 35% up to $626,350; 37% above. MFJ thresholds are doubled for most brackets. Standard deduction is not applied here; enter your taxable income (after deduction).
Strategic Roth conversion tips
- Convert during low-income years: early retirement years before Social Security and RMDs begin are often ideal.
- Fill your current bracket: convert only up to the top of your current bracket to avoid paying a higher rate on the marginal dollars.
- A Roth conversion reduces future Required Minimum Distributions (RMDs), which are required from Traditional IRAs starting at age 73.
- Pay the tax from non-IRA funds to maximize the amount that ends up in your Roth account compounding tax-free.
- State taxes also apply to conversions in most states; check your state's treatment of IRA conversions.
Frequently asked questions
What is a Roth conversion?
A Roth conversion is the process of moving funds from a pre-tax Traditional IRA (or 401(k)) into a Roth IRA. The converted amount is included in your taxable income for the year and taxed as ordinary income. After conversion, the funds grow tax-free and qualified withdrawals are tax-free.
When does a Roth conversion make sense?
A Roth conversion is most beneficial when your current tax rate is lower than your expected future rate, when you have a low-income year (such as early retirement before Social Security begins), when account values are temporarily depressed, or when you want to reduce future Required Minimum Distributions.
Is the converted amount subject to the 10% early withdrawal penalty?
No. The 10% early withdrawal penalty does not apply to Roth conversions, regardless of your age. However, if you withdraw the converted funds from the Roth IRA within 5 years, a 10% penalty may apply to those specific funds if you are under age 59.5 (the 5-year rule for conversions).
How much can I convert without moving to a higher tax bracket?
Calculate the gap between your current taxable income and the top of your current bracket. Any conversion amount within that gap is taxed at your current marginal rate. Converting beyond that amount pushes some dollars into the next higher bracket. This calculator shows the bracket headroom based on your taxable income.
Should I use IRA funds or outside money to pay the conversion tax?
Financial planners generally recommend paying the conversion tax from outside (non-retirement) funds rather than from the IRA itself. Paying from IRA funds reduces the amount converted and the future tax-free growth, and using pre-tax IRA funds to pay taxes is itself a taxable distribution (potentially with penalty if under 59.5).
Official sources
- IRS Publication 590-A: Contributions to Individual Retirement Arrangements (IRAs)
- IRS: FAQs: IRA Rollovers and Roth Conversions
Reviewed by the CalculatorHub team, edited by James Graham, 15 June 2026. See our methodology.