Roth conversion tax calculator
Enter your income before the conversion and the amount you plan to convert. The calculator shows the extra federal tax, how much room is left in your bracket and whether the conversion pushes you into an IRMAA tier.
Rules: 2026 federal tax yearResult
Fill in your numbers and press Calculate. The answer shows the formula and the rules it used.
Signed in, INDYXQUANT plans conversions year by year from your real IRA balances, Social Security and RMD schedule.
Do this with your real portfolioHow it is worked out
Taxable income before = AGI minus the 2026 standard deduction. The converted amount is ordinary income, so taxable income after = before plus the conversion.
Tax on the conversion = bracket tax after minus bracket tax before, using the 2026 brackets.
Medicare premiums two years later are set on this year's MAGI, so a large conversion can move you into a higher IRMAA tier.
Questions
How is a Roth conversion taxed?
The pre-tax amount converted is added to your ordinary income for the year and taxed at your marginal rates. There is no 10% early-withdrawal penalty on the conversion itself.
What does "room left in your bracket" mean?
The amount you could convert before the next dollar is taxed at a higher rate. Filling a bracket is a common way to size conversions.
Does a conversion affect Medicare?
It can. Medicare Part B and D premiums for a year are based on MAGI from two years earlier, so a conversion this year can raise premiums two years from now.
Sources
- IRS Rev. Proc. 2025-32 (2026 inflation adjustments)
- IRS Publication 590-A
- CMS 2026 Medicare premiums fact sheet
Rules: 2026 federal tax year. This page is for education and is not tax, legal or investment advice.