What is a Roth conversion analysis?

It is the tax work behind four decisions: whether to convert at all, how much to convert, in which years, and from which accounts. A conversion is taxed as ordinary income in the year you do it, and what it costs depends entirely on what else is already on the return underneath it. The analysis prices the conversion against your actual numbers instead of a rule of thumb.

How much does a Roth conversion actually cost in tax?

It depends on the year you do it. In the worked example, a married couple drawing $40,000 from a traditional IRA pays $12,360 of federal tax on a $100,000 conversion at 63 before Social Security starts, $18,013 on the identical conversion at 68 once benefits are on the return, and $18,687 at 76 once required distributions are filling the low brackets. Same conversion, three different bills, and finding the cheapest years is the job.

What does the analysis look at?

Your bracket before and after the conversion, how much of your Social Security the conversion drags into taxable income, the Medicare IRMAA line two years out, the required minimum distributions building underneath, your state's treatment, which onboarding captures so anything needing a state-specific rule check gets flagged, and where the conversion sits against the rest of your withdrawal sequence. The figures on this page come from the same engine that runs a client file.

Roth conversion analysis

A Roth conversion analysis answers four questions: whether, how much, which years, which accounts.

A conversion is taxed as ordinary income in the year you do it. What it costs depends on everything else already sitting on the return underneath it, which is why the same conversion is cheap in one year and expensive three years later. The analysis prices it on your actual numbers and says how much to convert and in which years.

Worked by Jim Swiech, CPA. We work virtually with retirement tax-planning clients across the U.S.

Reviewed by Jim Swiech, CPA · Updated September 16, 2026

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Who this is for

People with money in a traditional IRA, 401(k), 403(b) or SEP, who are in or near the stretch between the last paycheck and the first required distribution. That stretch is usually where the low brackets have the most room.

It also matters more than usual if one spouse is likely to outlive the other by a long stretch, because the survivor usually ends up filing as a single filer with narrower brackets, or if you are thinking about moving to a different state.

What we need from you

Usually your last two tax returns, your account balances by type, your pension and Social Security figures, when you plan to stop working, roughly what you spend, and the state you live in. If a piece is missing, we tell you what it would change rather than guessing at it.

What the analysis looks at

All of these run in the same model, because moving any one of them moves the others.

Your bracket, before and after. A conversion is included in income for the year of the distribution under 26 U.S.C. section 408A(d)(3), and the 2026 federal brackets and standard deduction come from IRS Rev. Proc. 2025-32. A conversion that spills into the next bracket buys its last slice at a higher rate than its first.
Social Security taxation. Converted income raises the figure the benefit test runs on, so a conversion can pull more of the benefit into taxable income on its way through. The inclusion thresholds are statutory and have never been indexed: 26 U.S.C. section 86. The tax torpedo page shows the spike.
The Medicare income line, two years out. Medicare sets your Part B and Part D premium from your income two tax years back, so a conversion this year decides a premium two years from now. The 2026 lines and premiums come from the CMS 2026 Part B premium notice: the first line for a couple is $218,000 of modified adjusted gross income, and one dollar over it takes the standard monthly premium from $202.90 to $284.10 per person.
Required minimum distributions. They begin at 73 for people born from 1951 through 1959 and 75 for those born in 1960 or later, per IRC 401(a)(9), as amended by SECURE 2.0 section 107. A dollar converted before then is a dollar that is no longer in the balance the distribution is calculated on, and a Roth IRA owner is not subject to lifetime required distributions at all under 26 U.S.C. section 408A(c)(5).
Withdrawal sequencing. Which account funds your spending, and which one pays the tax on the conversion, changes the cost of the conversion itself.
Your state. Every state treats a conversion differently. Onboarding captures the state you live in, so anything that needs a state-specific rule check gets flagged before we plan around it. New York, for example, taxes the converted amount but lets people 59½ and older exclude up to $20,000 per person of pension and annuity income, including IRA distributions, a single allowance the conversion has to share with anything already using it, per the New York State Department of Taxation and Finance guidance for seniors. The New York page runs the numbers.

What the difference is worth

A married couple, both the same age, drawing $40,000 a year from a traditional IRA. Same conversion, three points in their retirement, all under 2026 law, run through the same engine that runs a client file.

Married filing jointly, 2026. Age 63 with no Social Security. Age 68 with $48,000 of benefits. Age 76 drawing $60,000, roughly what a required distribution looks like at that age, plus the same benefits.
Convert	At 63	At 68	At 76
$25,000	$2,660 (10.6%)	$4,950 (19.8%)	$3,096 (12.4%)
$50,000	$5,660 (11.3%)	$7,950 (15.9%)	$6,367 (12.7%)
$100,000	$12,360 (12.4%)	$18,013 (18.0%)	$18,687 (18.7%)
$150,000	$23,360 (15.6%)	$30,333 (20.2%)	$31,064 (20.7%)

Read the $100,000 row. $12,360 at 63, $18,013 at 68, and $18,687 at 76. The couple at 68 is paying 18.0% on money that would have cost 12.4% with a different set of income underneath it, because the conversion dragged $17,800 of their Social Security into taxable income on the way through. Your own numbers will land somewhere else, but the shape of the answer is usually the same.

The dollar figures in this example are computed at build time by the same engine behind the public Roth conversion calculator, and a test fails the build if the prose and the engine ever disagree.

What you receive

A written plan, built on multi-year tax projections, that carries the conversion decision alongside the Medicare IRMAA, required minimum distribution and withdrawal sequencing decisions rather than in isolation. Meetings are virtual.

A year-by-year withdrawal plan is a separate engagement, and so is an ongoing year-round relationship, available as an ongoing engagement if you want the plan kept current as the law and your situation move.

Do I have to move my money?

A Go Beyond Tax tax-planning engagement does not require you to move your investments or replace your current financial advisor. We build the tax plan and, with your permission, coordinate the tax recommendations with the professionals you already use.

We share the tax recommendation with your advisor or custodian, and they handle the transaction. We do not direct it and we are not in the middle of it.

How fees work

Fees are flat and quoted before work begins, after a free call. The call is 30 minutes and costs nothing.

Read the math first, if you would rather

All of it is free to read. Start at the Roth conversion hub for the calculator, or go straight to the question you came with. The whole picture, including RMDs, Social Security and IRMAA, sits on the retirement tax planning page.

Want this run on your actual return?

Free 30-minute call with Jim. Bring your latest return and your account balances. You leave knowing whether a conversion is worth analyzing in your case and what the analysis would cost.

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Quick answers

What is a Roth conversion analysis?: It is the tax work behind four decisions: whether to convert at all, how much to convert, in which years, and from which accounts. A conversion is taxed as ordinary income in the year you do it, and what it costs depends entirely on what else is already on the return underneath it. The analysis prices the conversion against your actual numbers instead of a rule of thumb.
How much does a Roth conversion actually cost in tax?: It depends on the year you do it. In the worked example, a married couple drawing $40,000 from a traditional IRA pays $12,360 of federal tax on a $100,000 conversion at 63 before Social Security starts, $18,013 on the identical conversion at 68 once benefits are on the return, and $18,687 at 76 once required distributions are filling the low brackets. Same conversion, three different bills, and finding the cheapest years is the job.
What does the analysis look at?: Your bracket before and after the conversion, how much of your Social Security the conversion drags into taxable income, the Medicare IRMAA line two years out, the required minimum distributions building underneath, your state's treatment, which onboarding captures so anything needing a state-specific rule check gets flagged, and where the conversion sits against the rest of your withdrawal sequence. The figures on this page come from the same engine that runs a client file.
What do you need from me to run it?: Usually your last two tax returns, your account balances by type, your pension and Social Security figures, when you plan to stop working, roughly what you spend, and the state you live in. If something is missing we tell you what it changes rather than guessing at it.
Do I have to move my accounts to have you do this?: A Go Beyond Tax tax-planning engagement does not require you to move your investments or replace your current financial advisor. We build the tax plan and, with your permission, coordinate the tax recommendations with the professionals you already use. In practice that means we share the tax recommendation with your advisor or custodian and they handle the transaction.

Updated September 16, 2026. Reviewed by Jim Swiech, CPA.

The figures and examples on this page are educational and general. They are not tax, legal or investment advice for any individual and not a recommendation to convert. Federal figures are 2026; New York figures use the 2025 rate schedule until a 2026 schedule is published. Your return has more lines than any example. Go Beyond Tax is a brand of Swiech Consulting LLC.