Can I contribute to both Roth and Traditional 401(k) in the same year?

Many employer plans let you split contributions between a Roth and a Traditional 401(k) in the same year, which some people use to build tax diversification — some money taxed now, some taxed later. Your combined contributions across both still count toward one shared annual limit set by the IRS. Check whether your specific plan supports this split.

What changed for high earners' catch-up contributions starting in 2026?

Under the SECURE 2.0 Act, starting in 2026 many higher-income employees who make catch-up contributions (available to those 50 and older) are required to make those catch-up contributions as Roth rather than pre-tax, if their prior-year wages from that employer were above a threshold set by law. This is a mandatory plan-design change, not optional, for the employees it affects. Confirm with your plan administrator whether it applies to you and how your specific plan implements it.

Home › Roth vs Traditional 401(k)

Roth 401(k) vs Traditional 401(k): Which Should You Choose in 2026?

Q: What is the main difference between Roth and Traditional 401(k)?

Traditional 401(k) contributions are made pre-tax, which lowers your taxable income now, but withdrawals in retirement are taxed as ordinary income. Roth 401(k) contributions are made with after-tax money, so they don't lower your taxable income today, but qualified withdrawals in retirement — including all investment growth — are generally tax-free. The choice largely comes down to whether you expect your tax rate to be higher or lower in retirement than it is now.

Q: Which should high earners choose in 2026?

There is no universal answer. Many higher earners lean Traditional because the upfront deduction offsets income taxed at a higher marginal rate today, on the assumption their retirement tax rate will be lower. Others choose Roth if they expect similar or higher tax rates later, want tax-free growth, or want to diversify. The right mix depends on your income, expected retirement tax rate, and how many years your money has to grow — a licensed tax professional can help model your specific situation.

General information for savers · Last reviewed: July 2026

Most 401(k) plans now let you choose between a Traditional (pre-tax) account and a Roth (after-tax) account — or split contributions between both. The decision comes down to one honest question: do you expect to pay a higher or lower tax rate now versus in retirement? This guide breaks down the difference, the 2026 rule change affecting some high earners, and how to think about the choice. Then use our 401(k) calculator to project either path.

Illustrative diagram of the core trade-off: pay tax now (Roth) or pay tax later (Traditional).

FTC disclosure: some links on this page are affiliate or internal cross-sell links. This never affects what we say about how these accounts work.

The core difference: when you pay the tax

A Traditional 401(k) takes contributions out of your paycheck before income tax is applied, which lowers your taxable income this year. In retirement, withdrawals — your contributions and all the growth — are taxed as ordinary income. A Roth 401(k) takes contributions after tax is already applied, so there's no deduction today, but qualified withdrawals in retirement, including all growth, are generally tax-free. Same investment menu, same employer plan — the only real difference is which side of retirement the tax bill lands on.

No income limit on Roth 401(k) — unlike a Roth IRA

One detail that surprises people: a Roth IRA has an income limit that phases out high earners, but a Roth 401(k) does not. If your employer plan offers a Roth option, you can use it regardless of how much you earn. That makes the Roth 401(k) the main way many higher earners access tax-free retirement growth at all.

The 2026 change: mandatory Roth catch-up for some high earners

Under the SECURE 2.0 Act, starting in 2026 employees age 50+ who make catch-up contributions and whose prior-year wages from that employer were above a threshold set by law are required to make those catch-up contributions as Roth, not pre-tax. This isn't optional for the employees it affects — it's a plan-design requirement. If you're in or approaching the catch-up age range, confirm with your plan administrator whether this rule applies to you and how your plan has implemented it.

1. Traditional 401(k)

Contributions reduce this year's taxable income; withdrawals are taxed as income later.

Best for: people who expect a lower tax rate in retirement than today

The catch: if tax rates rise, or your retirement income is higher than expected, you could owe more tax later than you saved now.

2. Roth 401(k)

Contributions use after-tax money now; qualified withdrawals — including growth — are generally tax-free later.

Best for: people who expect a similar or higher tax rate later, or who want tax diversification

The catch: no upfront tax break, so your paycheck takes a bigger hit today for the same contribution amount.

3. Splitting between both

Many plans let you contribute to both Traditional and Roth in the same year, sharing one combined annual limit.

Best for: hedging against not knowing your future tax rate

The catch: more accounts to track, and it doesn't remove the need to think through your overall strategy.

Traditional vs Roth at a glance

Question	Traditional	Roth
When is it taxed?	Withdrawals, in retirement	Contributions, today
Lowers taxable income now?	Yes	No
Growth taxed?	Yes, as income at withdrawal	No, if withdrawal is qualified
Income limit to contribute?	No	No (unlike a Roth IRA)
Best guess needed	Your retirement tax rate is lower than today's	Your retirement tax rate is similar or higher than today's

Contribution limits are set annually by the IRS and change every year — always confirm the current figures at irs.gov or with your plan provider rather than relying on a remembered number.

Project your 401(k) balance

Try both a Traditional and Roth contribution split in the calculator to compare outcomes.

Frequently asked questions

What is the main difference between Roth and Traditional 401(k)?

Traditional is taxed later (on withdrawal), Roth is taxed now (on contribution) with generally tax-free qualified withdrawals later. The better choice depends on whether your tax rate will be higher or lower in retirement.

Is there an income limit for Roth 401(k) contributions?

No. Unlike a Roth IRA, a Roth 401(k) has no income limit, so high earners can use it if their employer plan offers the option.

Can I contribute to both in the same year?

Many plans allow splitting contributions between Roth and Traditional, sharing one combined IRS annual limit. Check whether your plan supports this.

What changed for high earners' catch-up contributions in 2026?

Under SECURE 2.0, starting in 2026 certain higher-income employees making catch-up contributions must make them as Roth, not pre-tax, if their prior-year wages from that employer exceeded a legal threshold. Confirm with your plan administrator whether this applies to you.

Which should high earners choose in 2026?

There's no universal answer — it depends on your current versus expected retirement tax rate, income, and goals. A licensed tax professional can help model your specific situation.

This page is general information for educational purposes only — not financial, investment, or tax advice. Rules for 401(k) contribution limits and catch-up requirements are set by the IRS and change over time. Always verify current details with your plan provider, the IRS, or a licensed tax professional before making a decision.

General references include published 2026 explainers from Fidelity, Charles Schwab, Kiplinger, and Ramsey Solutions on Roth vs Traditional 401(k) accounts, and coverage of the SECURE 2.0 high-earner catch-up rule change. Always verify current rules with the IRS or your plan provider.