Roth Conversion Tax Buffer Calculator
Work out how much you can still convert to a Roth IRA before breaching your current marginal tax bracket. Provide your projected taxable income and the bracket ceiling to see remaining headroom, estimated taxes on a chosen conversion amount, and any spillover into higher rates.
Educational estimate only—confirm tax projections with your CPA before executing a Roth conversion.
Examples
- $142,000 income, $190,750 bracket ceiling, 24% rate, $35,000 conversion ⇒ Headroom before next bracket: $48,750.00 USD • Estimated tax on $35,000.00 converted at 24.00%: $8,400.00 USD • No overflow when converting this amount.
- $188,500 income, $190,750 ceiling, optional fields blank ⇒ Headroom before next bracket: $2,250.00 USD • Estimated tax on $2,250.00 converted at 22.00%: $495.00 USD • No overflow when converting this amount.
FAQ
What if I expect additional income later in the year?
Add the projected income to your taxable income input now so the remaining headroom reflects the higher year-end total before you execute a conversion.
How should I handle state income taxes?
Use the optional marginal rate field to blend in your state percentage. For example, a 22% federal bracket plus 5% state rate would use 27%.
Can I test multiple conversion sizes?
Yes. Enter a planned conversion amount to see how much remains in the current bracket versus how much would spill into the next bracket at higher rates.
Does this account for IRMAA or NIIT surcharges?
No. Layer those analyses separately by checking Medicare IRMAA thresholds or net investment income tax triggers alongside this bracket buffer result.
Additional Information
- Bracket ceilings change annually; update the input with the current IRS schedule for your filing status.
- Taxable income should include all expected ordinary income and deductions for the year, not just the Roth amount.
- The marginal rate defaults to 22% when left blank so you still receive an estimated tax bill on the modeled conversion.