What is a Roth conversion?

A Roth conversion is the process of moving money from a pre-tax retirement account, such as a traditional IRA or 401(k), into a Roth IRA. You pay income tax on the converted amount in the year of conversion, but future qualified withdrawals from the Roth IRA are tax-free.

When does a Roth conversion make sense?

A Roth conversion can make sense if you expect to be in the same or a higher tax bracket in retirement, if you have cash outside your IRA to pay the conversion tax, if you want to reduce future required minimum distributions (RMDs), or if you want to leave tax-free assets to heirs.

How is the tax on a Roth conversion calculated?

The converted amount is added to your other taxable income for the year. It is then taxed at your marginal income tax rates. Our calculator approximates this by applying your current marginal rate to the converted amount, but your actual tax will depend on your full income picture and deductions.

Should I pay Roth conversion tax from the IRA or from other savings?

Paying the tax from outside savings is usually more favorable. It allows the full converted amount to stay in the Roth IRA and grow tax-free. Paying tax from the IRA reduces the amount that ends up in the Roth and can trigger penalties if you are under age 59½.

Can I undo a Roth conversion?

No. Since 2018, the IRS no longer allows recharacterization of Roth conversions. Once you convert, it is irrevocable. That is why it is important to model the tax impact and long-term outcomes before converting.

Roth Conversion Calculator: Optimize Your IRA Conversion Strategy

Estimate taxes on a Roth conversion, compare keeping your traditional IRA vs converting to Roth, and explore multi-year conversion strategies.

Scenario	At retirement	After-tax at retirement	After-tax at end of horizon
Keep all in traditional	–	–	–
Convert as modeled	–	–	–

Year	Age	Trad balance	Roth balance	After-tax total
Run the calculation to see the projection.

How this Roth conversion calculator works

This tool compares two simplified strategies:

Scenario A – Keep traditional: You leave your full balance in a traditional IRA/401(k). It grows tax-deferred, and withdrawals are taxed at your expected retirement tax rate.
Scenario B – Convert to Roth: You convert some or all of your traditional balance to a Roth IRA, pay tax now, and let the Roth grow tax-free. Any remaining traditional balance continues to grow tax-deferred.

Key assumptions

Constant annual pre-tax investment return.
Constant marginal tax rate now and in retirement (you can set them separately).
No additional contributions.
No early withdrawal penalties modeled.
RMD rules are ignored to keep the comparison transparent.

Core formulas

Tax on conversion

\(\text{Tax}_{now} = \text{Amount converted} \times \text{Current tax rate}\)

Future value of an account

\(\text{FV} = \text{PV} \times (1 + r)^n\)

where \(r\) is the annual return and \(n\) is the number of years.

After-tax value of traditional assets

\(\text{After-tax trad} = \text{Trad balance} \times (1 - \text{Retirement tax rate})\)

Breakeven year

The calculator estimates the first year when the after-tax value of the Roth-conversion strategy exceeds the after-tax value of keeping everything in traditional accounts, under your assumptions. If that never happens within the modeled horizon, the breakeven is reported as “never”.

When a Roth conversion can be attractive

You expect higher tax rates in the future (personal or legislative changes).
You have cash outside your IRA to pay the conversion tax.
You want to reduce future RMDs and keep more flexibility in retirement.
You plan to leave assets to heirs and prefer they receive tax-free Roth assets.

When a Roth conversion may not make sense

You are currently in a very high tax bracket and expect a much lower bracket in retirement.
You must pay the tax from the IRA itself, especially if you are under 59½ (possible penalties).
You are close to retirement and won’t give the Roth much time to grow.

Limitations and next steps

This calculator is an educational tool. It does not:

Model detailed U.S. tax brackets, deductions, or credits.
Account for Social Security taxation, Medicare surcharges, or state taxes.
Incorporate RMD schedules or changing tax laws.

Before executing a large conversion, consider running a detailed tax projection or consulting a qualified tax professional or financial planner.

Frequently asked questions

Is there an income limit for Roth conversions?

No. Since 2010, there is no income limit on who can convert traditional IRA or eligible employer-plan assets to a Roth IRA. However, your ability to make new Roth contributions may still be limited by income.

Can I do partial Roth conversions over several years?

Yes. Many investors “ladder” conversions over multiple years to stay within a desired tax bracket. Use the multi-year option in this calculator to approximate an even spread of conversions until retirement.

How does a Roth conversion affect RMDs?

Roth IRAs are not subject to RMDs during the original owner’s lifetime, while traditional IRAs and most employer plans are. Converting reduces the balance subject to future RMDs, potentially lowering taxable income in retirement.

Roth Conversion Calculator

1. Inputs

2. Summary

Tax impact now

Breakeven estimate

3. Traditional vs Roth – Future Value

4. Year-by-Year Projection (simplified)