Roth vs Traditional 401(k) Calculator 2026

Roth vs Traditional 401(k) Calculator

A traditional 401(k) cuts your taxes now; a Roth 401(k) makes withdrawals tax-free later. Enter your salary and contribution to see the paycheck cost of each and which is likely to win.

● 2026 $24,500 limit ● Paycheck cost compared ● Bracket-aware guidance

⚖️ Compare the two

When are you taxed?

The one question that decides it

Both accounts let you save the same amount toward retirement. The only real difference is timing of tax:

Traditional 401(k) — contributions are pre-tax. They lower your taxable income now, so your paycheck drops by less than the amount you contribute. You pay ordinary income tax when you withdraw in retirement.
Roth 401(k) — contributions are after-tax. Your paycheck drops by the full amount, but qualified withdrawals in retirement are 100% tax-free, including all the growth.

The rule of thumb: if your tax rate in retirement will be lower than today, traditional usually wins. If it will be higher (or you are young and early-career), Roth usually wins.

A worked comparison

Take a single filer earning $85,000 contributing 8% ($6,800). In the 22% bracket, the traditional version saves about $1,496 in federal tax this year, so it only costs about $5,304 of take-home. The Roth version costs the full $6,800 of take-home now — but every dollar it grows to is tax-free at retirement. The calculator shows that ~$1,500 annual paycheck difference.

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Match is always pre-tax. Even if you choose Roth, your employer's matching contribution goes into a traditional (pre-tax) bucket. See the match math on the 401(k) contribution calculator.

Why young savers often pick Roth

Early in a career, your income — and tax bracket — is usually at its lowest. Paying tax now at a low rate and locking in decades of tax-free growth is a strong bet. As income climbs into the 24%+ brackets, the immediate deduction of a traditional 401(k) becomes more valuable.

Roth vs Traditional 401(k) Calculator FAQ

What is the difference between a Roth and traditional 401(k)?

A traditional 401(k) is funded with pre-tax dollars — you get a tax break now and pay tax on withdrawals later. A Roth 401(k) is funded with after-tax dollars — no break now, but qualified withdrawals are tax-free. The contribution limit ($24,500 in 2026) is shared across both.

Which is better, Roth or traditional?

If you expect a lower tax rate in retirement than today, traditional usually wins. If you expect a higher rate, or you are early in your career at a low bracket, Roth usually wins because it locks in tax-free growth.

Does a Roth 401(k) lower my paycheck more?

Yes. Roth contributions are after-tax, so your take-home drops by the full contribution. A traditional contribution lowers taxable income, so your paycheck drops by less — the difference equals your contribution times your marginal tax rate.

Can I split between Roth and traditional?

Yes, most plans let you contribute to both in any split, as long as your combined deferral stays within the $24,500 (2026) limit. Many savers hedge by doing some of each.