A Roth conversion tool for licensed professionals

A joint Roth conversion is two conversions, one tax return, and a dozen allowances that are granted per person.

RothWise™ runs the whole calculation for a married couple filing jointly — two ages, two IRAs, two conversion schedules — and hands you a report you can put in front of your client the same day.

See how it works Where every figure comes from

Why the joint case is the hard one

Their incomes combine. Their IRAs cannot.

A couple files one return, so the tax is computed on the household. But an IRA belongs to one person, so each conversion is separate — and the single tax owed has to be attributed back to each spouse in a way that still adds up.

They reach 73 in different years.

Required withdrawals begin on each person's own schedule. A model that treats a couple as one taxpayer with one start date gets the middle years wrong, and the middle years are where a conversion window lives.

Several allowances are per person, not per couple.

The additional deduction at 65, the senior deduction, the state retirement exclusion and the Medicare surcharge are each granted individually. Doubling a single-filer figure is only right when both spouses qualify.

What you enter, and what your client receives

You enter what you already have

Entered once, per person where it differs.
Both ages	Each spouse's own date drives their own required-withdrawal start.
Both IRA balances	Held separately. They are never pooled.
Both Social Security benefits	Taxed on the household, computed from each benefit.
Other income	Pensions, interest, dividends, earned income.
State	Sets the state retirement exclusion each spouse is entitled to.
Filing status	Married filing jointly.

Your client receives a report

Prepared under your name. Fixed page order.
The Conversion Plan	Both conversion schedules, year by year.
How Your Effective Rate Is Built	The deductions and exclusions each spouse gets, shown separately.
Scenario Comparison	Converting against doing nothing, on equal terms.
Your Roth, Individually	A Roth result for each of them.
Roth Conversion Detail	One page per spouse, every year of the conversion.
Required Distributions If You Don't Convert	One page per spouse, the withdrawals they avoid.
Medicare IRMAA Impact	The surcharge, with the enrolled count changing as each turns 65.

The three figures on the cover

Hypothetical example

Every report opens with the three numbers a client actually asks about. The figures below are from a sample household, not a real one.

Lifetime tax
reduction

$907,242

Tax paid under the conversion plan against tax paid doing nothing.
Additional net
spendable value

$3,617,420

Roth tax-free value less the status-quo value.
Shown per
spouse

Both

Each conversion, each required-withdrawal schedule and each Roth, individually.

Why it holds up when someone checks it

The calculation is built to be examined. Every constant traces to a published source, the source and the date it was read are recorded in the engine, and the parts of the law that are still unsettled are printed in the report rather than smoothed over.

Every figure taken directly from authoritative government sources. Not a blog, a vendor page or a search summary. The date each source was read is recorded alongside the figures it produced, so anything in the report can be traced back on request.
The vintage of the law is recorded, not implied. The inflation-adjusted amounts reflect the Code as in effect on 9 October 2025, and the engine carries that date rather than presenting the figures as timeless.
Per-person allowances are computed per person. The additional deduction at 65, the senior deduction, the state retirement exclusion and the Medicare headcount are each resolved for each spouse.
The two scenarios are compared on equal terms. Both are grown at the same rate and both reinvest their net required distributions, so neither column is flattered by its assumptions.
The per-person tax split is disclosed as an attribution. One joint return owes one tax. The report divides that single amount between the spouses in proportion to the distribution each took that year, and says so in those terms — it is an attribution, not a second tax bill.
What is not modelled is declared. The additional deduction for blindness is named as outside the model rather than quietly omitted.
Unsettled law is printed, not buried. The required-withdrawal age for people born in 1959 rests on a proposed regulation, and the report says so and cites the conflict in the statute.
The caveats are generated from the constants. They are produced by the same code that holds the figures, so a caveat cannot fall out of step with the number it describes.
Figures that did not match their source are disclosed in the engine rather than rounded away.
The report is traceable end to end. Every number on the cover is reachable from a page that shows the year-by-year arithmetic behind it.

Who it's for

Registered investment advisers
A conversion analysis you can show a client and defend line by line, with the assumptions stated plainly on the page.
Insurance professionals
The same calculation and the same report, prepared under your name, covering both spouses separately.
Anyone handling the joint case
Two ages, two IRAs, two withdrawal schedules and a Medicare surcharge that changes when the second spouse turns 65 — worked out rather than estimated.

Questions

Whose name is on the report?

Yours. The cover carries your prepared-by block, and the client reads it as your work.

Does it handle a couple where only one spouse is 65?

Yes, and that case is the reason the Medicare page exists. The surcharge is charged per enrolled person, so it is charged once on the full joint income while only one of them is enrolled, and twice once both are. The enrolled count changes down the table.

Why can't the two IRAs just be added together?

Because an IRA belongs to one person. The balances drive separate conversion schedules and separate required withdrawals, even though the tax is computed on the household.

How is the effective rate on the conversion worked out?

It is not a tax bracket. It is the first year's tax divided by the first year's distribution, and the report builds that figure line by line so you can see which allowances applied to which spouse.

Where do the tax figures come from?

Directly from authoritative government sources. The date each one was read is recorded alongside the figures it produced, and where a point of law is not settled the report says so rather than glossing over it.