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Retirement

Roth Conversion Calculator

Enter your conversion amount, tax rates, and time horizon to see whether converting to Roth makes financial sense for your situation.

Updated July 2026 · Editorial standards

Retirement tax avoided by converting
$48,371
Roth value at retirement (tax-free)
$193,484
Traditional after-tax value
$145,113
Tax cost to convert now (paid from outside savings)$11,000Years to grow20 yrsRate now22%Rate in retirement25%

Conversion Details

$
yrs
yrs
%
%

Key figures

Retirement tax avoided by converting
$48,371
Roth value at retirement
$193,484
Traditional after-tax value
$145,113
Tax cost to convert now
$11,000

Converting $50,000 avoids the 25% retirement tax on the grown balance — $48,371 of retirement tax you never pay. This assumes the $11,000 conversion tax is paid from savings outside the IRA, so the full amount keeps growing tax-free.Growth over 20 years at 7%: Roth = $193,484 tax-free. Traditional = $193,484 gross → $145,113 after 25% tax.

Retirement tax avoided by converting
$48,371
By KalkWiseVerified against official sources Updated July 2026

What is the roth conversion calculator — is converting worth it??

In short

Converting $50,000 from a traditional IRA to Roth at age 45, at a 22% tax rate, costs $11,000 in taxes today. At 7% annual growth, by retirement at 65 the Roth holds $193,484 tax-free vs. $145,113 from traditional after 25% taxes — a $48,371 net advantage from converting at the lower rate.

This Roth conversion calculator compares the after-tax retirement value of converting a traditional IRA or 401(k) to Roth now versus leaving it as a traditional account. It models the tax cost today, growth over your investment horizon, and the after-tax value at retirement under each path, then shows which option leaves you better off.

How to use this calculator

  1. 1Enter the amount you want to convert this year.
  2. 2Enter your current age and the age you plan to start retirement withdrawals.
  3. 3Enter your current marginal federal tax rate (the bracket your conversion income will fall into).
  4. 4Enter your projected tax rate in retirement — higher than today favors converting now.
  5. 5Enter your expected annual investment return and compare the Roth vs. traditional outcome.

The formula

Rothret=C×(1+r)n
Tradret=C×(1+r)n×(1−t₂)
Tax cost today = C × t₁. Roth value at retirement = C × (1+r)ⁿ (tax-free). Traditional value at retirement = C × (1+r)ⁿ × (1−t₂) (taxed at withdrawal). Converting is advantageous when t₁ < t₂ — you pay tax at the lower current rate instead of the higher future rate. If rates are equal, the Roth and traditional produce identical after-tax outcomes.
C
— Conversion amount
t₁
— Current marginal tax rate
t₂
— Projected retirement tax rate
r
— Annual investment return
n
— Years until retirement

Worked example

The scenario

$50,000 conversion at age 45, retirement at 65, current rate 22%, retirement rate 25%, 7% annual return.

gives

The result

Tax cost now: $11,000. Growth over 20 years at 7%: $50,000 × 3.8697 = $193,484. Roth value: $193,484 (tax-free). Traditional value: $193,484 × (1 − 0.25) = $145,113. Net Roth advantage: $193,484 − $145,113 = $48,371. Converting at 22% beats paying 25% later by $48,371.

Common use cases

  • Converting during a low-income year (job change, early retirement) when your rate is temporarily lower.
  • Converting before age 73 RMDs force large traditional IRA withdrawals into higher brackets.
  • Anticipating higher tax rates in retirement due to pension + SS + RMD income stacking.
  • Estate planning: Roth IRAs have no RMDs during the owner's lifetime and pass tax-free to heirs.

Limitations & assumptions

  • Assumes you pay conversion taxes from outside funds — if you pay taxes from the IRA itself, the math changes significantly.
  • Does not model state income taxes on the conversion (conversion is taxable in most states).
  • Investment returns are assumed constant — actual returns will vary year to year.
  • Does not account for IRMAA surcharges on Medicare premiums, which can spike in the year of a large Roth conversion.
  • Applies one flat marginal rate to the entire conversion — large conversions actually span multiple brackets, so the real tax is usually between your current and next bracket rates.
  • Assumes the conversion tax is paid from money outside the IRA and does not credit what those dollars could have earned elsewhere — at equal current and retirement rates the calculator therefore still shows an advantage equal to the retirement tax avoided.

Frequently asked questions

A Roth conversion makes sense when your current marginal tax rate is lower than your expected rate in retirement. Common windows: early retirement before Social Security and RMDs kick in (ages 59½–72), years with large deductions or business losses, or a year when Congress is considering rate increases. At equal rates, Roth and traditional produce the same after-tax result.

Disclaimer: KalkWise calculators are provided for general informational and educational purposes only and do not constitute financial, investment, tax, or legal advice. Results are estimates based on the figures you enter and the assumptions described above. Actual outcomes will vary. Consult a qualified professional before making financial decisions.