Roth vs. Traditional Calculator
Compare the after-tax outcome of Roth (post-tax) versus traditional (pre-tax) retirement contributions, given your tax rate today and in retirement. The comparison reinvests the up-front tax savings a traditional deduction produces, so the totals are apples to apples.
Compare the two account types
Amount contributed each year, up to $1,000,000.
Hypothetical annual rate from -20% through 30%.
Your marginal tax rate now, used for the traditional deduction.
Expected marginal rate when you withdraw, used to tax traditional withdrawals.
Whole number from 1 through 60.
The traditional account leaves you with more spendable money after taxes in this scenario.
- Roth after-tax total
- $566,764.72
- Traditional after-tax total
- $578,100.01
- Pre-tax future value
- $566,764.72
| Component | Roth | Traditional |
|---|---|---|
| After-tax account value | $566,764.72 | $442,076.48 |
| Reinvested up-front tax savings | — | $136,023.53 |
| Total after-tax value | $566,764.72 | $578,100.01 |
The traditional column assumes you invest the up-front tax savings from each deductible contribution — its own line above — rather than spending them. Without reinvesting those savings, traditional would fall short of Roth in most scenarios.
How the after-tax comparison is calculated
Both accounts start from the same pre-tax future value: the annual contribution grown as an annuity at the expected return. A Roth contribution is made with money you have already paid tax on, so its balance is entirely after-tax. A traditional contribution is deducted now and taxed on withdrawal, so its balance is reduced by your retirement tax rate — but the deduction hands you a tax saving today, which this model reinvests and grows the same way.
FV = PMT × (((1 + r)t − 1) / r); Roth = FV; Traditional = FV × (1 − tret) + FVsavings- FV
- Pre-tax future value of contributions
- PMT
- Annual contribution
- r, t
- Annual return and number of years
- tret
- Tax rate applied to traditional withdrawals
- FVsavings
- Grown value of the up-front tax savings (contribution × tax rate today), reinvested each year
Whichever account ends with the larger total after-tax value is flagged as coming out ahead. When your tax rate is higher today than in retirement, the traditional deduction is worth more, which often tips the result toward traditional.
$6,000 a year for 30 years, 24% now vs. 22% later
Contributing $6,000 per year for 30 years at a 7% return, with a 24% tax rate today and 22% in retirement, the Roth account ends at $566,764.72 after tax. The traditional account is worth $442,076.48 after the 22% withdrawal tax, plus $136,023.53 from reinvesting the up-front tax savings — a total of $578,100.01.
Because the traditional total edges out the Roth total by about $11,335, traditional comes out ahead here. The deciding factor is that the 24% deduction today is worth slightly more than the 22% tax paid on withdrawal.
This is an educational comparison. It does not model tax brackets, required minimum distributions, or state and provincial taxes.
What this calculator assumes
- The same contribution amount and return apply to both accounts for the full period.
- The traditional up-front tax savings are invested, not spent, and grow at the same return.
- A single flat tax rate applies today and a single flat rate applies in retirement — no bracket-by-bracket modeling.
- Contribution limits, income phase-outs, required minimum distributions, and state or provincial taxes are not modeled.
- Fees and inflation are excluded.
Roth vs. traditional FAQ
Why does the traditional column add a second line?
A traditional (pre-tax) contribution lowers your taxable income now, producing an immediate tax saving. To compare fairly with Roth, this tool assumes you invest that saving rather than spending it, and grows it alongside the account. That reinvested saving is shown as its own line so the total is transparent.
Which one should I choose?
It depends mostly on whether your tax rate is higher now or in retirement, plus factors this tool does not model. A higher rate in retirement tends to favor Roth; a higher rate today tends to favor traditional. This is an educational comparison, not a recommendation — talk with a qualified tax or financial professional about your situation.
Sources and review notes
Methodology last checked Jul 14, 2026. Formula implementation is covered by deterministic unit tests. No financial professional review is claimed yet.