Roth Conversion Calculator
A Roth conversion is a bet on tax rates: pay income tax on the converted amount today in exchange for tax-free growth and withdrawals later. This calculator shows the after-tax outcome of converting versus staying traditional under your assumptions.
Simplified model: the outcome is driven by today's rate vs the future rate. Paying the conversion tax from money outside the account tilts the result further toward converting. Ignores IRMAA, state taxes, and the pro-rata rule — talk to a tax professional before converting.
Illustrative only, based on the assumptions you enter — not a quote, an offer, or financial advice. Rates and rules change; verify current figures with a licensed professional before acting.
How this calculator works
If your tax rate were identical now and in retirement, converting and not converting produce the same after-tax result — the commutative property of multiplication, not magic. The case for converting is a lower rate today than later; the case against is the reverse.
This model assumes the conversion tax is paid out of the converted amount, which is the conservative case. Paying the tax from a separate taxable account effectively shelters more money in the Roth and tilts the comparison further toward converting.
Real conversions have second-order effects the simple model ignores: conversions stack on top of other income and can push you into a higher bracket, raise Medicare IRMAA surcharges two years later, and interact with the pro-rata rule if you hold pre- and post-tax IRA money.
Frequently asked questions
When do conversions tend to make sense?
Classic windows are low-income years — early retirement before RMDs and Social Security begin, a sabbatical, or a market dip when the same shares convert at a lower taxed value.
Is there a limit on how much I can convert?
No dollar limit — but every converted dollar is ordinary income that year, so large conversions are usually spread across years to manage brackets.
Can I undo a conversion?
No. Recharacterization of conversions was eliminated by the 2017 tax law, so a conversion is final — size it carefully.
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This tool is for general education only and is not financial, tax, or legal advice. Results are illustrations based on your inputs — not quotes or guarantees. Consult a licensed professional before making decisions about annuities, settlements, or retirement accounts.