What this estimate means
A Roth conversion moves dollars from a traditional (pre-tax) retirement account into a Roth account. The converted amount is generally taxable as ordinary income in the year of conversion. This calculator estimates the extra federal ordinary income tax caused by adding that conversion on top of your other income — by comparing tax with and without the conversion under illustrative 2026 brackets.
Important product boundary: Retirement Planning Center’s year-by-year projections do not currently calculate income tax, tax brackets, or conversion ladders. We still offer this page as a free educational resource so you can explore the topic without pretending the planner “optimizes” conversions. See Taxes in our methodology.
How the math works
Optionally subtract the 2026 standard deduction from your “other income,” then compute progressive federal tax on taxable income before and after adding the conversion. The difference is the estimated tax cost of the conversion. Effective rate = that tax ÷ conversion amount. Traditional balance remaining is a simple subtraction for illustration.
What we intentionally leave out
- State income tax
- Net Investment Income Tax (NIIT), IRMAA surcharges, and Medicare premium interactions
- Taxation of Social Security benefits when AGI rises
- Pro-rata / basis rules across multiple IRAs
- 5-year rules, recharacterizations, and backdoor Roth mechanics
- Multi-year “fill the bracket” optimization
Those omissions are why this is a resource calculator — not a claim that our planner performs tax-aware conversion planning like some competitors.
How this page differs from our other free tools
- RMD calculator — mandatory distribution estimates with Uniform Lifetime divisors.
- Spending / longevity / market tools — cash-flow and market stress without conversion tax.
- Full free plan — accounts and projections; still without income-tax modeling today.
Important limitations
Educational estimate only — not tax, legal, or investment advice. Bracket tables change; verify IRS publications for the year you care about. Consult a qualified tax professional before converting.
Prefer a full household walkthrough? Explore Jim & Susan’s sample plan. Or create a free account to organize traditional vs Roth balances even while tax analytics remain on the roadmap.