Roth vs Traditional 401(k) Calculator
Same paycheck, two tax treatments. See whether Roth or Traditional 401(k) contributions leave you with more after-tax money in retirement, and the tax rate where the answer flips.
1Salary and contribution
$
Enter your contribution as
%
You defer $8,000 per year into the plan.
2Employer match
%
%
Your employer adds $2,400 per year. A 50% match pays 50 cents per dollar you contribute, up to the cap.
3Taxes and growth
%
%
Use your combined federal plus state marginal rates. For retirement, use the rate your withdrawals will actually face, often below your working-years bracket. You enter both rates yourself, so the tool never depends on tax brackets that go stale.
yr
%
Traditional tax savings
Fair comparison: the paycheck advantage goes into the taxable side account every year.
%
Rate applied each year to the returns of the taxable account holding the Traditional tax savings. Set 0% for no tax drag, or your income tax rate to mirror typical bank calculators.
4Split strategyOptional
%
The rest goes to Traditional. The match is unaffected.
After 30 years
Roth +$15,789
Roth leaves you $15,789 better off. Your retirement rate (22%) is above the breakeven rate of 19.9%.
Traditional
$916,728
401(k) after tax$589,435Invested tax savings+$150,462Match after tax+$176,831Total cost of taxes−$247,029Whole balance taxed at withdrawal, plus a taxable side account
RothEnds ahead
$932,517
401(k), tax-free$755,686Match after tax+$176,831Total cost of taxes−$49,875Taxed today, withdrawals tax-free; only the match is taxed
After-tax value over time
TraditionalRoth
$970k
$727k
$485k
$242k
$0
Roth ahead from year 17
Now6y12y18y24y30y
Traditional wins if your retirement marginal rate stays below 19.9%. You entered 22%. Traditional starts ahead thanks to the invested tax savings, but Roth overtakes it in year 17.
A 50% Roth / 50% Traditional mix ends at $924,623 after tax, $7,894 behind the better pure choice. A mix can never beat the winner in a fixed scenario; its value is insurance against guessing your future tax rate wrong.
If your retirement rate turns out differentTap to apply
Annual contribution$8,000
Annual employer match$2,400
Annual tax savings invested (24%)$1,920
Pre-tax plan balance at retirement$982,392
Breakeven retirement tax rate19.9%
The employer match always lands in a pre-tax account, even next to Roth contributions. It is taxed at your retirement rate in both scenarios and adds $176,831 after tax.
Embed on your site Last updated: July 2026
How to use this calculator
Roth or Traditional, answered in four steps.
1
Enter salary and contribution
Set your current annual salary and how much you defer into the 401(k), either as a percent of pay or as a dollar amount.
2
Add the employer match
Enter the match rate and the salary cap it applies to, for example 50% of contributions up to 6% of salary. The match is identical in both scenarios.
3
Set your two tax rates
Enter your marginal tax rate today and the marginal rate you expect in retirement. The gap between these two rates drives the whole decision.
4
Read the verdict
Compare the after-tax totals, check the breakeven retirement rate, and watch both balances grow year by year in the chart.
Key concepts
How the Roth vs Traditional trade-off really works.
Traditional 401(k)
Contributions leave your paycheck before income tax, cutting today's tax bill. Every dollar withdrawn in retirement is taxed as ordinary income.
Roth 401(k)
Contributions are taxed like normal salary today. In exchange, qualified withdrawals in retirement, contributions and all growth, are completely tax-free.
Marginal tax rate
The tax rate on your last dollar of income. Traditional contributions avoid tax at this rate today; Traditional withdrawals pay it in retirement.
Employer match
Money your employer adds when you contribute, typically a percentage of your deferral up to a salary cap. It always goes into a pre-tax account, whichever type you pick.
Breakeven retirement rate
The retirement tax rate at which both choices end with the same after-tax value. Below it Traditional wins, above it Roth wins.
Invested tax savings
A Traditional contribution leaves extra cash in your paycheck today. A fair comparison assumes you invest that saving; otherwise Traditional gets no credit for it.
Tax drag
The invested tax savings sit in a taxable account whose returns are taxed every year, so it compounds more slowly than the 401(k). That is why the breakeven rate sits below today's rate.
Required minimum distributions
Traditional accounts force taxable withdrawals from your early 70s. Roth money rolled into a Roth IRA can keep compounding untouched for life.
Tips before you choose
Get more out of every 401(k) dollar.
Capture the full match first
Whatever you decide on Roth vs Traditional, contribute at least enough to earn the entire employer match. It is an instant, guaranteed return no tax strategy can beat.
Split when you are unsure
You can direct part of your deferral to Roth and part to Traditional. Tax diversification hedges you against whichever way rates move by the time you retire.
Early career favors Roth
Low salary years mean a low marginal rate today. Paying that small rate now and never again is usually cheap insurance, especially with decades of growth ahead.
Peak earnings favor Traditional
In your highest-earning years the deduction is worth the most, and most people drop to a lower bracket once the paycheck stops.
Actually invest the savings
The Traditional advantage assumes the tax saved lands in an investment account. If it quietly disappears into spending, Roth wins far more often than the math suggests.
Revisit after big changes
A raise, a move to another state, or a new tax law can shift your rates. Rerun the comparison whenever your marginal rate changes materially.
FAQ
What is the difference between a Roth and a Traditional 401(k)?+
Traditional contributions are made pre-tax and withdrawals are taxed as ordinary income. Roth contributions are made after tax and qualified withdrawals are tax-free. The employer match is pre-tax in both cases. Which one wins depends mostly on your marginal tax rate today versus in retirement.
What are the 401(k) contribution limits?+
The IRS sets an annual employee deferral limit ($24,500 in 2026, with an extra catch-up from age 50 and a higher one at ages 60 to 63) that is shared across Roth and Traditional contributions combined. The limit changes most years, so check the current IRS figure. This calculator deliberately does not enforce it; it compares the tax treatment of whatever amount you enter.
Is the employer match Roth or pre-tax?+
Traditionally the match always went into a pre-tax account, even when you contribute Roth, so it is taxed at withdrawal. Since SECURE 2.0 employers may offer a Roth match, but few plans do. This calculator uses the standard pre-tax treatment in both scenarios.
Why does the calculator invest the Traditional tax savings?+
A Traditional contribution costs you less take-home pay than the same Roth contribution, because it cuts today's tax bill. Comparing the accounts alone would ignore that extra cash. The fair comparison invests the annual tax saving in a taxable account and adds it to the Traditional side.
What is the breakeven retirement tax rate?+
It is the retirement marginal rate at which both choices end with exactly the same after-tax value. If you expect to retire below it, Traditional wins; above it, Roth wins. With no tax on the side account it equals your current rate; the annual tax drag pushes it lower.
Will my tax rate really be lower in retirement?+
Often, but not always. Many retirees drop to a lower bracket because the paycheck stops, but large Traditional balances, required minimum distributions, Social Security taxation, and future rate increases can push the rate back up. Also enter the rate your withdrawals will actually face: they fill the lower brackets first, so the blended rate is often below the headline bracket, which favors Traditional. That uncertainty is a core argument for Roth or for splitting.
Can I contribute to both at the same time?+
Yes. Most plans let you split your deferral between Roth and Traditional in any proportion, as long as the combined amount stays within the IRS limit. Splitting is a popular hedge when you cannot predict future tax rates.
What about required minimum distributions (RMDs)?+
Traditional 401(k) balances face RMDs from age 73 (rising to 75), forcing taxable withdrawals whether you need the money or not. Roth 401(k) accounts no longer have RMDs since 2024, and Roth IRAs never did, so Roth money can compound untouched.
Does this also apply to Roth vs Traditional IRAs?+
The core math is identical: pre-tax now and taxed later versus taxed now and tax-free later. IRAs differ in limits, income phase-outs, and the absence of an employer match, so ignore the match section when using this tool for an IRA decision.
What if tax rates rise in the future?+
Higher future rates make Roth more attractive: you lock in today's known rate and become immune to increases on that money. If you believe rates must rise substantially by your retirement, treat your entered retirement rate as conservative and lean Roth or split.
Both scenarios defer the same dollar amount into the plan; contributions are credited at the end of each year and compound at your expected return. Traditional additionally invests its annual tax saving (contribution times your current marginal rate) in a taxable side account whose returns are taxed every year at the rate you choose, so it compounds at the reduced rate. Setting that rate to your income tax rate mirrors the standard bank calculators; 0% removes the drag entirely. The employer match is pre-tax in both scenarios and is taxed at your retirement rate. The breakeven retirement rate is the side account's final value divided by the pre-tax employee balance. You can also mark the savings as spent, which removes the side account and shows the no-discipline case. Pure math with the rates you enter: no tax brackets, no statutory limits, nothing to go out of date. Illustrative, not tax advice.
Fair comparison with invested tax savings · user-entered marginal rates, no statutory tables · USD, illustrative, not tax advice