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Roth Conversion Calculator

See whether Roth conversions deserve a closer look in your situation, and roughly how much bracket room you have — free, no sign-up required.

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Why we ask: We need this to compute your result. Estimates work.

Disclaimer: This tool provides educational estimates only. Actual Roth conversion outcomes depend on detailed tax situations. Consult a qualified tax professional.

This is a screening tool. It answers one question — do Roth conversions deserve serious attention in your situation, or not — and it shows you the reasoning behind the answer instead of just a verdict. It is deliberately not a tax calculation, and the section below is precise about where it stops.

What the tool does, and where it stops

You answer six questions: your age, whether you have retired, whether you have started Social Security, roughly how large your pretax balances are, your current annual income, and your filing status. It returns a candidacy signal — strong, moderate, or weak — along with the specific reasons behind that signal and a rough estimate of how many years your low-income conversion window may run.

It also shows a bracket-headroom figure: how much more ordinary income fits before you cross the top of the federal bracket you are currently in — the 10%, 12%, 22%, or 24% ceiling, whichever is yours. It is measured net of the standard deduction, and it names the tax year whose brackets it used. Above the 24% bracket it gives a qualitative answer instead of a figure.

It is still a screen, not a return. The figure assumes ordinary income and the base standard deduction — no extra deduction for age 65 or older, no itemizing — and capital gains, the taxable-Social-Security calculation, and state tax all move the real ceiling. What a screen is genuinely good for is deciding whether this is worth your time — and if it says yes, the next step is a real calculation against your actual return.

Why "how much" is the harder half of the question

Whether to convert at all is usually the easier call: if your marginal rate today is lower than your expected rate later, converting is favorable. Sizing is where the real money is, because the cost of a conversion is not smooth. It steps.

Federal brackets step. State income tax may step, or may not apply at all. And for anyone near Medicare age, an income-related premium adjustment is a genuine cliff rather than a slope — one dollar over a tier boundary triggers the entire surcharge for that tier, assessed from the income you reported two years earlier. A conversion sized to the bracket but blind to that boundary can cost more than it saves.

That is why no screening tool can give you the number, and why "convert until just under the next threshold" is a more useful rule than any fixed figure. The right amount changes every year even when your plan does not.

What this tool does and does not model

It estimates

  • Whether your situation structurally favors conversions, with the reasons shown
  • A rough estimate of how many years your low-income window may run
  • Bracket headroom — the room left before your income crosses the top of your current federal bracket, net of the standard deduction and labeled with the tax year applied

It does not model

  • Any tax computation — it never asks for a conversion amount and never returns tax owed
  • Anything on your return beyond ordinary income and the base standard deduction — no extra deduction for age 65 or older, no itemizing
  • State and local income tax — which for some filers is the largest single factor
  • Your existing IRA basis and the pro-rata rule across all pretax IRAs
  • Net Investment Income Tax, and ACA premium tax credits if you are under 65
  • Capital gains stacking, QBI interactions, and the taxable-Social-Security calculation

Frequently Asked Questions

Sizing and estimation questions about Roth conversions. For what a conversion is and how the five-year rule works, see Roth Conversion Basics below.

  • How much should I convert to a Roth in one year?

    The common approach is to convert up to the top of your current tax bracket and stop, so every converted dollar is taxed at a rate you already know. This tool shows you that ceiling — the room left before your income crosses the top of your current bracket — as a starting scale. It is not the final number: if you are close to Medicare age the tighter ceiling is usually the next income-tier boundary rather than the bracket, and your own return carries deductions and income types the screen does not see.

  • What does this calculator actually estimate?

    A candidacy signal — strong, moderate, or weak — plus the reasons behind it, a rough count of the years your low-income window may run, and a bracket-headroom figure: the room left before your income crosses the top of the federal bracket you are currently in, labeled with the tax year applied. It is not a tax computation: it never asks for a conversion amount and never returns tax owed. It assumes ordinary income and the base standard deduction, so confirm against your actual return before sizing a conversion.

  • Does the estimate include state income tax?

    No. State treatment varies too much to model generically — several states levy no income tax at all, while others tax conversions as ordinary income at rates that can exceed the federal difference you are trying to capture. If you live in a taxing state, add your state marginal rate to the cost before deciding.

  • Are there income thresholds the bracket math misses?

    Yes, and one of them is a cliff rather than a slope. For anyone at or near Medicare age, an income-related premium adjustment is assessed in tiers based on the income you reported two years earlier, so crossing a tier boundary by a single dollar triggers that entire tier. The calculator does not model it. If you are within a couple of years of 65, check your distance to the next tier boundary before sizing a conversion to the bracket alone.

  • Do I need an account or have to enter identifying information?

    No. There is no account, no email requirement, and nothing that identifies you. Do not enter your Social Security number, Medicare number, or account numbers — no legitimate retirement calculator needs them, here or anywhere else.

  • When is the conversion window usually widest?

    In the years after wage income stops and before RMDs begin — and, if you are delaying Social Security, before those benefits start. Income is temporarily low in that stretch, so the same conversion costs less tax. The RMD age depends on your birth year, so it is worth confirming yours rather than assuming.

  • Can I change my mind after converting?

    No. Recharacterizing a conversion was eliminated for conversions made in 2018 and later, so a conversion is irreversible once done. That is the main argument for converting in measured annual amounts rather than one large transfer.

  • Is this personalized tax advice?

    No. NestPilot Foundation is a 501(c)(3) educational nonprofit. We sell nothing, take no fees, and receive no commissions. This is education and arithmetic you can verify — for a decision this size, confirm the numbers against your actual return with a qualified tax professional.

Primary Sources

Read more about Roth conversions

Last reviewed 2026-10-11. NestPilot Foundation is a 501(c)(3) nonprofit. We sell nothing, take no fees, and receive no commissions.