Roth Conversion & IRMAA Optimizer
Nearly every free Roth calculator asks what a conversion costs this year. That is the wrong question. The expensive consequences arrive later: Medicare surcharges land two years after the income that triggers them, they are cliffs rather than ramps, and the largest cost of all usually arrives when one spouse dies and the survivor starts filing single on the same required distributions. This model runs the whole horizon, twice, and shows you the difference.
Recommended within the range modelled
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Adjust the inputs to see a result.
Your next IRMAA cliff
- Lifetime tax — no conversion
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- Lifetime tax — converting
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- Medicare surcharges paid
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- Ending after-tax wealth
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Why the answer is not simply “convert more”
Each point is a different annual conversion amount. If Medicare surcharges did not exist this line would be smooth. The steps down are IRMAA cliffs — places where converting one more dollar costs a full bracket, for both spouses, for a year.
The year-by-year detail
The figures above are yours to keep — no email required, and they update as you type. What sits below is the schedule behind them: every year, the conversion, the resulting MAGI, which IRMAA bracket it lands in two years later, and what that costs. Send it to yourself and I will include the two or three things in your specific numbers that are worth a conversation.
Sent — the detail is below
Book the 30-minute call| Year | Age | Convert | RMD | MAGI | IRMAA tier | Surcharge | Fed tax | Pre-tax bal. | Roth bal. |
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How this projection works, and what it cannot do
Criteria and methodology
- The model runs your situation year by year from now to the end year you choose, twice: once converting nothing, and once converting the amount you selected each year. It reports the difference.
- Each year it computes federal ordinary income tax on a stacked basis, the taxable portion of Social Security using the provisional-income formula, the 3.8% net investment income tax where the threshold is crossed, and the Medicare Part B and Part D income-related surcharges — applied to the year they actually land, which is two years after the income that triggers them.
- Required minimum distributions begin at your applicable age under SECURE 2.0 and are computed from the projected balance using the IRS Uniform Lifetime Table.
- It also models the OBBBA senior deduction phase-out, which withdraws six cents of deduction per dollar of income and is the reason a conversion inside that band costs more than its stated bracket.
Assumptions and limitations
- A single constant rate of return, applied to every account. Real returns are neither constant nor identical across account types, and sequence matters — this model contains no sequence risk at all.
- Today's tax law, held constant and inflated at a fixed rate. Brackets, IRMAA thresholds and the senior deduction all change annually, and the senior deduction is scheduled to lapse after 2028.
- Florida residency, and therefore no state income tax, unless you select another state.
- Conversion taxes paid from taxable assets, not withheld from the conversion. Paying the tax from the IRA materially reduces the benefit and is not modelled.
- No state estate tax, no charitable strategy, no QCDs, no Medicaid or ACA subsidy interaction, and no change in filing status other than the survivor scenario if you enable it.
- This is a planning estimate, not a tax return. It will not match a preparer's figure to the dollar and is not intended to.
Investments considered
- This tool selects among tax timing strategies, not among investments. It does not recommend, screen, rank or select any security, fund, manager or product, and no investment universe is considered.
- The only choice it evaluates is how much pre-tax retirement money to convert to Roth in each year, across the range you set. It reports the schedule with the lowest projected lifetime cost within that range and under the assumptions above.
Applies to every result this tool produces
- Results are hypothetical in nature. They are produced by a model, not by any account, and no client obtained them.
- Results vary with each use and over time — with the figures you enter, with the assumptions above, and with changes in tax and Medicare law, which change annually.
- This tool does not consider your full circumstances and is not investment, tax, or legal advice. Using it does not create an advisory relationship.
Important Disclosures. Wolfson Private Wealth, LLC ("WPW") is an investment adviser registered with the Florida Office of Financial Regulation. Registration does not imply a certain level of skill or training. All investment strategies have the potential for profit or loss. Past performance is not indicative of future results.
Information presented on this website is for educational and informational purposes only, does not constitute investment, tax, legal, or accounting advice, and should not be construed as a solicitation, offer, or recommendation to buy or sell any security. Any client scenarios described are hypothetical composites for illustrative purposes only and do not represent any specific client, actual performance, or guarantee of results.
WPW does not offer tax or legal advice. Clients should consult qualified tax and legal professionals regarding their individual circumstances. Tax and Medicare parameters change annually; figures shown reflect published 2026 amounts and are projected forward under stated assumptions.