Roth Conversion Calculator

What is a Roth conversion?

A Roth conversion moves money from a traditional retirement account into a Roth IRA. You generally include the converted amount in taxable income for the year of the conversion. In return, qualified withdrawals from a Roth IRA can be tax-free. The calculator compares the estimated value of converting with the estimated value of leaving the money in a traditional account.

The Roth conversion calculator is a planning tool, not a prediction of your future tax bill. The comparison depends on the tax rate you enter now, the rate you expect at withdrawal, how long the money may grow, the assumed annual return, and whether you pay the conversion tax from outside funds.

Why a Roth conversion matters

A conversion brings a tax cost forward. That may be worthwhile if you expect your tax rate at withdrawal to be equal to or higher than your rate now. If you expect a lower rate later, paying tax now may reduce what you keep. Your answer can affect how much cash you keep available for retirement, other goals, or unexpected expenses.

How you pay the tax also matters. If you use money outside the retirement account, more of your retirement savings can remain invested. But those outside funds have an opportunity cost: they could otherwise grow, and the calculator accounts for tax drag on outside savings when that input applies. Paying the tax from the retirement account can reduce the amount left to grow. Consider the effect on your cash reserves before making a decision.

A Roth conversion can affect your taxable income and other parts of your tax picture. Consider the timing and ask a tax professional to confirm how a conversion may apply to you.

How to use this Roth conversion calculator

1. Enter the amount you are considering converting. Use the amount you expect to move from the traditional account to the Roth IRA.
2. Enter your estimated tax rate on the conversion and your estimated tax rate at withdrawal. These are planning assumptions, not guaranteed future rates.
3. Enter the years until you expect to withdraw the money and the annual return you want to model. Consider testing different assumptions rather than relying on one forecast.
4. Indicate whether you plan to pay the conversion tax with money outside the retirement account, if that option appears. Enter the tax drag on outside savings when relevant.
5. Review the estimated tax due now, the projected Roth value, the traditional account value after tax, and the difference between the two. Change one assumption at a time to see which inputs most affect the comparison.

Roth conversion calculator example

How to read your Roth conversion result

“Converting comes out ahead by” is the calculator’s estimated difference between the two modeled outcomes. A positive difference favors converting under the assumptions you entered. A smaller difference, or a result favoring the traditional account, means the choice may be sensitive to your assumptions.

“Tax now” is the estimated tax cost of the conversion. Compare that cost with the projected values, but do not treat a favorable long-term estimate as a reason to overlook the cash needed today. The Roth and traditional values are projections through your stated withdrawal horizon. Actual returns, tax rates, and account rules may differ.

How to make your conversion decision more useful

1. 01

   Test more than one tax-rate scenario

   Run the calculator with several reasonable estimates for your future tax rate. If the result changes sharply, treat the decision as uncertain and discuss the assumptions with a tax professional.

2. 02

   Check where the tax payment will come from

   Review your cash reserves and planned expenses before using outside funds. If paying the tax would leave you short for a home repair, debt payment, or other near-term need, include that tradeoff in your decision.

3. 03

   Compare partial conversions

   Consider testing a smaller conversion amount instead of assuming you must convert everything at once. A partial conversion can help you compare outcomes while limiting the amount of income added in the current year. Ask a tax professional how the amount may affect your return.

4. 04

   Keep the assumptions grounded

   Use a return assumption and withdrawal timeline that fit your plan, and test alternatives. A result is only as useful as the inputs behind it.

Common Roth conversion mistakes

• Treating the projected result as guaranteed

  The calculator models assumptions. It cannot know future investment performance or your tax rate when you withdraw. Use the result to compare scenarios, not to promise a specific balance.

• Ignoring the cash cost today

  A conversion can create a tax bill before you receive any retirement withdrawals. Make sure you account for the tax payment and the effect of using outside savings.

• Entering the same tax rate without testing alternatives

  The comparison may look different if your future rate is higher or lower. Check how sensitive the result is before relying on a single estimate.

• Overlooking your full tax picture

  The calculator focuses on the conversion comparison. It does not assess every detail of your return or personal circumstances. Confirm the tax treatment and timing with a qualified tax professional.

The roth conversion formula

Key terms

Roth conversion

A transfer of money from a traditional retirement account into a Roth IRA that may create taxable income in the year of the transfer.

Tax rate on conversion

The rate used to estimate the tax cost of converting the amount entered.

Tax rate at withdrawal

The estimated rate used to calculate the tax on traditional-account withdrawals in the comparison.

Tax drag on outside savings

The calculator input for the effect of taxes on outside funds used in its comparison.