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Roth vs Traditional 401(k) Calculator

Which 401(k) wins for you? Fair take-home comparison with employer match.

By Mubeen Khan · Last reviewed 2026-10-16

Your numbers

Winner (after tax)
Roth 401(k)
Roth 401(k) value at retirement
$1,337,027.09
Traditional 401(k) value at retirement
$1,337,027.09
Difference
$0.00
Annual take-home cost (identical both ways)
$7,800.00
Roth annual contribution (same paycheck hit)
$7,800.00
Employer match per year
$2,400.00
Match value at retirement (after tax)
$258,779.44
Lifetime tax paid - Roth path
$149,989.07
Lifetime tax paid - Traditional path
$377,110.20
Years invested
35
Equal-take-home comparison: the Roth contribution is sized so both choices reduce your paycheck by the same amount - the only fair way to compare. Employer match is always pre-tax and taxed at withdrawal in both paths. Simplified model: year-end contributions, constant tax rates and returns, no IRS contribution limits, RMDs, or early-withdrawal penalties. Actual results depend on your tax situation.

Breakdown

After-tax balance growth over time

How this calculator works

Most Roth vs Traditional calculators cheat: they compare equal contributions, but $10,000 into a Roth costs you more take-home pay than $10,000 pre-tax into a Traditional - so the comparison is rigged from the start. This Roth vs Traditional 401(k) calculator normalizes by take-home cost: it sizes the Roth contribution so both choices shrink your paycheck by the identical amount, then grows both to retirement with your expected return. It also models the employer match correctly (match dollars always land pre-tax and get taxed at withdrawal, no matter which side you pick).

The math behind the verdict is simple once the comparison is fair. If your tax rate in retirement will be lower than today, Traditional usually wins - you dodge tax at a high rate now and pay at a low rate later. If you expect higher taxes in retirement (raises, required minimum distributions, fewer deductions), Roth pulls ahead because you lock in today's rate. When the rates are equal, the two tie almost exactly - the calculator will show you. Play with the retirement tax rate slider: it is the single input that flips most verdicts, which is why the honest answer to "Roth or Traditional?" is always "it depends on your future tax rate."

Frequently asked questions

Should I choose Roth or Traditional 401(k)?
It hinges on your tax rate now vs in retirement. Higher rate now → Traditional usually wins. Higher rate in retirement → Roth usually wins. Enter both rates above - the calculator gives you a personalized verdict.
Why do most Roth vs Traditional calculators get it wrong?
They compare equal contribution dollars, but a Roth dollar costs more take-home pay than a pre-tax Traditional dollar. This calculator normalizes by take-home cost so the comparison is apples to apples.
What happens to the employer match in a Roth 401(k)?
Employer matching dollars always go into a pre-tax (Traditional) account, even if your contributions are Roth. The match grows tax-deferred and is taxed as ordinary income when you withdraw it - the calculator models this.
Is Roth better for young workers?
Often yes, because young workers are usually in lower tax brackets with decades of tax-free growth ahead. But it is not automatic - a young high earner in the 32% bracket may still favor Traditional. Run your numbers above.
What tax rate should I assume for retirement?
A common starting point is your current marginal rate minus a few points (retirees often have lower taxable income), but required minimum distributions and Social Security taxation can push it up. Try a range - the verdict slider shows how sensitive the answer is.

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Disclaimer: Results are estimates for planning purposes only and are not financial advice. Actual loan terms, taxes and investment returns vary. Consult a qualified professional before making financial decisions.