401(k), IRA & Roth
A Roth conversion calculator for the December 31 decision
A Roth conversion calculator that shows the tax due now, paid from outside funds, against the long-run after-tax value of converting or not, at the rates the client enters.
Included on every plan, even the free Practitioner plan. No card needed.
Is a Roth conversion worth it?
A conversion makes sense when the tax paid now, at today's marginal rate, is lower than the tax the money would face later, and when the tax can be paid from outside the IRA. Converting in low-income years, before RMDs begin at 73 (born 1951–1959); 75 (born 1960 or later)2026 · IRS, is the classic window. Conversions must be completed by December 31.
November, with the December 31 deadline ahead
Early retirees, people between jobs and anyone with an unusually low-income year hear that this is the time to convert. Conversions count in the calendar year they're made, so the question becomes urgent in the fourth quarter. Clients want to know the tax bill and whether it pays off before they call.
What the client types into a search box
“should I do a roth conversion this year”
How a client works through it
Enter the amount to convert
The pre-tax IRA amount the client is considering.
Set time and return
Years until the money is needed and the annual return.
Enter tax rates
Today's marginal rate and the expected rate in retirement.
Compare outcomes
Roth value, no-conversion value, the advantage and the tax due now.
What lands in your inbox
When a client asks your firm to review the result, the request arrives as a contact record with their inputs and results attached, by email and, on paid plans, by webhook to your CRM.
Received
Conversion amount, years, return and the two tax rates show the client's thinking. A large conversion amount may push the client into higher brackets or Medicare surcharges. A lower expected retirement rate than today's suggests conversion may not pay, which is worth explaining.
How does the calculator treat the tax money?
Tax Due on Conversion is paid from outside funds. In the no-conversion case, that same money is assumed to stay invested in a taxable account, so the comparison is fair. No Conversion (After-Tax, incl. Tax Money Invested) adds both pieces.
Conversion Advantage is positive when converting wins at the rates entered. Future Pre-Tax Balance shows what the IRA would grow to unconverted.
Results shown: Roth Value (After Conversion) · No Conversion (After-Tax, incl. Tax Money Invested) · Conversion Advantage · Tax Due on Conversion · Future Pre-Tax Balance.
Why do firms want Roth conversion requests?
Conversions are multi-year tax planning: how much to convert each year to fill a bracket, how it affects Medicare premiums and Social Security taxation, how to pay the tax. It's high-value work, and a request that arrives in November is actionable.
For advisers, conversions also involve moving assets and rebalancing between account types.
Follow-ups this request opens
- Size a partial conversion to fill the current bracket
- Check Medicare IRMAA thresholds two years ahead
- Plan how to pay the tax from outside the IRA
- Schedule conversions across several years before RMDs
What this calculator leaves out
- Rates hold as entered; a large conversion can push income into higher brackets.
- Medicare IRMAA surcharges and Social Security taxation are not modeled.
- Assumes tax is paid from outside funds.
- The five-year rule for converted amounts is not modeled.
Platform disclaimer shown under the calculator: Estimates only. Assumes the conversion tax is paid from outside funds; if you don't convert, that money is assumed to stay invested in a taxable account (gains taxed at your retirement rate). Rates hold as entered; conversions can affect your tax bracket, IRMAA and more. Consult a tax professional.
Compliance note for firms
Conversion advice is complex written tax advice under Circular 230 §10.37: it should consider bracket thresholds, IRMAA, state tax and the source of tax payments. Advisers should present long-run comparisons as hypothetical, and conversions are irreversible, which clients should hear clearly.
Not legal advice. See our disclaimer and the guide to compliance for client calculators.
2026 figures this page relies on
| Figure | Value | Tax year | Source |
|---|---|---|---|
| RMD starting age (SECURE 2.0) | 73 (born 1951–1959); 75 (born 1960 or later) | 2026 | IRS |
The same values drive the calculator. Full list on the 2026 figures page.
Terms your client sees in the calculator
These definitions appear in the calculator's collapsible Definitions block, so clients don't have to call to ask what a label means.
- Roth conversion
- Moving money from a traditional, pre-tax IRA or 401(k) into a Roth account. The converted amount is added to your taxable income for that year, but future qualified withdrawals are tax-free. This calculator compares converting now, with the tax paid from outside funds, against leaving the balance pre-tax and keeping that tax money invested instead.
- Tax rate now vs. in retirement
- The comparison that drives most conversion decisions. If your marginal rate in retirement will be lower than today, leaving money pre-tax usually comes out ahead; if it will be higher, converting usually does. When the two rates are equal, the result here turns mostly on the tax money kept invested in a taxable account, whose gains are taxed.
- Tax due on conversion
- The income tax owed on the converted amount, figured here as the amount converted times your current marginal rate. A large conversion can push part of the income into a higher bracket, so the real bill may exceed this estimate. Paying it from outside savings, rather than from the converted funds, keeps the full balance growing tax-free.
- Conversion advantage
- The Roth value minus the after-tax value of not converting, including the tax money kept invested in a taxable account. A positive figure favors converting under your assumptions; a negative one favors staying pre-tax. It is sensitive to the two tax rates and to the years of growth, so testing a range of rates is more useful than a single result.
- Traditional (pre-tax) account
- An IRA or workplace plan funded with money that has not yet been taxed. It grows tax-deferred, and withdrawals are taxed as ordinary income. In this comparison, the future pre-tax balance is reduced by your expected retirement tax rate to show what you would actually keep if you do not convert.
- Tax-free growth
- Earnings inside a Roth account that are never taxed as long as withdrawals are qualified. After a conversion the full balance compounds and comes out tax-free, while a taxable side account loses part of its gains to tax. This calculator compounds both monthly at the annual return you enter.
In our glossary: Roth conversion · Marginal tax rate · Required minimum distribution
Roth Conversion calculator: questions from firms and clients
When is the deadline for a Roth conversion?
December 31 of the tax year. Unlike contributions, conversions can't be made after year-end for the prior year.
Can a conversion be undone?
No. Recharacterizing conversions is no longer allowed.
Should I pay the tax from the IRA?
Usually not; paying from outside funds keeps more in the Roth. Under 59½, tax withheld from the conversion may also face the early-withdrawal penalty.
How much should I convert?
Often enough to fill the current bracket. The marginal tax rate calculator shows how much room is left.
Does a conversion affect Medicare premiums?
It can, two years later, through IRMAA. The calculator doesn't model it; the firm should check.
Is converting before RMDs useful?
Often, because it reduces future RMDs, which begin at 73 (born 1951–1959); 75 (born 1960 or later)2026 · IRS.
Does the five-year rule apply?
Converted amounts have a five-year period for penalty-free withdrawal before 59½.
Which plan includes it?
Every plan, including the free Practitioner plan, which runs up to 5 calculators at once alongside the other retirement tools. Firm (up to 50) and Network (no cap) add webhooks and white-label. See pricing.
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Clients who ask this usually ask next
Marginal Tax Rate
what tax bracket am I in and what happens if I earn more
Roth vs. Traditional
should I choose roth or traditional 401k
Required Minimum Distribution (RMD)
how much do I have to take out of my IRA this year
All “401(k), IRA & Roth” calculators · Everything in Retirement
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