How to use this calculator
- Enter the inputs using consistent units.
- Review rate, timing, and scope assumptions.
- Select Calculate to update every result.
- Change one assumption at a time to compare scenarios.
#3309 · Finance Tool
Roth Conversion After Tax Value Calculator
Compare the projected after-tax value of converting pre-tax retirement assets to Roth today versus leaving them pre-tax. Enter current and future tax rates, growth, and holding period to estimate the Roth advantage or disadvantage.
Calculator
Enter assumptionsFormula
Roth net value = Roth balance − future value of outside tax paid; Traditional net value = balance × (1 − future tax rate)
If tax is paid from the account, the converted principal is reduced immediately instead.
What the result means
The difference is sensitive to current versus future marginal rates and the source of conversion tax. It does not model brackets, Medicare premiums, required distributions, state moves, or early-withdrawal penalties.
This is an educational estimate, not tax, legal, or investment advice. Tax rules, eligibility, account ordering, and state treatment vary; confirm decisions with a qualified professional.
Example calculation
Converting $100,000 at 24%, growing 15 years at 7%, and paying tax outside produces a Roth balance of $275,903. The future value of the $24,000 tax is $66,217, so net Roth value is $209,686. Traditional after-tax value at 30% is $193,132, a Roth advantage of about $16,554.
Tips for better results
- Keep units consistent from input through result.
- Use unrounded values during the calculation and round only the displayed result.
- Run a conservative and an optimistic scenario before acting.
- Document assumptions so the estimate can be reproduced.
Frequently asked questions
Why subtract the future value of tax paid from outside cash?
That cash could otherwise have been invested, so its opportunity cost is included for a fairer comparison.
What if conversion tax is paid from the retirement account?
The calculator reduces the amount entering Roth by the current tax due.
Does the calculator model progressive tax brackets?
No. Enter an effective marginal rate for the conversion slice and future withdrawal.
Are qualified Roth withdrawals always tax-free?
Eligibility and holding-period rules apply; the model assumes the compared Roth withdrawal is qualified.
Does this include required minimum distributions?
No. It compares a single amount and does not model distribution schedules.
Related calculators
Roth comparison paths
| Path | After-tax treatment |
|---|---|
| Roth | Qualified future value is modeled tax-free |
| Traditional | Future balance reduced by the entered tax rate |
| Outside tax cash | Opportunity cost compounded at the same return |