A traditional 401(k) lets you contribute before tax, then taxes the withdrawals in retirement. A Roth 401(k) flips that: you contribute after tax, get no deduction now, and qualified withdrawals in retirement, including all the growth, are tax-free. It has the high contribution limits of a 401(k) and, unlike a Roth IRA, no income limit.

Introduced in 2006, a Roth 401(k) blends the after-tax structure of a Roth IRA with the employer-sponsored, payroll-deducted format of a 401(k).

Key features of a Roth 401(k)

After-tax contributions. You pay income tax on the money before it goes in, then it grows tax-free.

Tax-free qualified withdrawals. In retirement, both contributions and earnings come out tax-free once you're at least 59 1/2 and have held the account five years or more.

No income limit. High earners who are phased out of a direct Roth IRA can still fund a Roth 401(k).

2026 contribution limit. You can contribute up to $24,500, plus an $8,000 catch-up at 50 or older, or $11,250 if you're between 60 and 63. This limit is shared with any traditional 401(k) contributions in the same year. If your prior-year wages from the employer topped $150,000, catch-up contributions must be made on a Roth basis, which a Roth 401(k) already satisfies.

Employer match. Traditionally, an employer match goes into a companion pre-tax account and is taxed on withdrawal even if your own contributions are Roth. Under SECURE 2.0, some plans now let you elect Roth treatment for the match; if you do, you pay tax on the match in the year it's made and it comes out tax-free later.

No required minimum distributions. As of 2024, a Roth 401(k) is not subject to lifetime RMDs, the same as a Roth IRA. (Pre-tax accounts still require RMDs starting at age 73, or 75 if you were born in 1960 or later.)

Benefits of a Roth 401(k)

Tax-free retirement income, which is most valuable if you expect a similar or higher tax rate later.

Tax diversification. Holding both a traditional and a Roth 401(k) lets you choose which account to draw from each year in retirement to manage your tax bill.

Estate planning. Qualified withdrawals are tax-free to your heirs as well.

Example: how a Roth 401(k) plays out

Meet Alex: 30 years old, $60,000 salary, currently in the 22% federal bracket, planning to retire at 65.

Alex contributes $5,000 a year to a Roth 401(k). Because it's after-tax, Alex pays the 22% tax on that $5,000 (about $1,100) out of the rest of the paycheck; the full $5,000 goes into the account.

Over 35 years at a 7% average annual return, $5,000 a year grows to about $691,000. Of that, roughly $175,000 is contributions and about $516,000 is earnings. Because the account has been open more than five years and Alex is over 59 1/2, the entire balance, contributions and earnings, comes out tax-free.

Had Alex used a traditional 401(k) instead, the $5,000 contributions would have lowered taxable income each year, but every withdrawal in retirement would be taxed as ordinary income. If Alex's tax rate in retirement is as high as or higher than 22%, the Roth comes out ahead.

Roth 401(k) vs. traditional 401(k)

Both offer tax advantages; the difference is timing.

Tax treatment. A Roth 401(k) taxes contributions now for tax-free withdrawals later. A traditional 401(k) skips tax now and taxes withdrawals in retirement as ordinary income.

Withdrawal rules. Roth 401(k) withdrawals are tax-free once the account is five years old and you're 59 1/2. Traditional 401(k) withdrawals are always taxed as income.

Required minimum distributions. Neither is subject to lifetime RMDs anymore in its Roth form; the traditional 401(k) requires RMDs at 73 (75 if born in 1960 or later). Since 2024, a Roth 401(k) has no lifetime RMDs, so the old "roll it into a Roth IRA to avoid RMDs" workaround is no longer necessary.

Early withdrawals. Both charge a 10% penalty on withdrawals before 59 1/2, with limited exceptions. A Roth 401(k) does not work like a Roth IRA here: you cannot pull out only your contributions tax- and penalty-free. A non-qualified early withdrawal is split pro-rata between contributions and earnings, and the earnings portion is taxed and penalized. See Roth 401(k) withdrawal rules for the detail.

Who each suits. A Roth 401(k) fits people who expect a similar or higher tax rate in retirement, or who want tax-free income and estate benefits. A traditional 401(k) fits people who expect a lower rate later and want the deduction now.

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History of the Roth 401(k)

The Roth story starts in 1997 with the Roth IRA, named for Senator William Roth of Delaware, which introduced after-tax contributions with tax-free growth and withdrawals, a departure from the pre-tax model.

The Economic Growth and Tax Relief Reconciliation Act of 2001 laid the groundwork for a workplace version, and the Roth 401(k) became available on January 1, 2006. It brought Roth tax treatment to employer plans and, importantly, to higher earners shut out of a Roth IRA by income limits.

Since then the Roth 401(k) has spread across employer plans, though not universally, driven by growing interest in tax diversification. Later legislation made it easier to roll traditional 401(k) balances into a Roth 401(k) within the same plan (an in-plan Roth conversion), and SECURE 2.0 removed lifetime RMDs for Roth 401(k)s and added the option for Roth employer contributions.

Final thoughts

Choosing between a Roth and a traditional 401(k) comes down to your tax rate now versus in retirement, your goals, and whether you value tax-free income and no RMDs. A financial advisor can model both against your numbers.

Frequently asked questions

What exactly is a Roth 401(k)?

A Roth 401(k) is an employer-sponsored retirement plan you fund with after-tax dollars. There's no deduction now, but qualified withdrawals in retirement, after age 59 1/2 and five years in the account, are tax-free, including all the investment growth.

Can I contribute to both a Roth 401(k) and a traditional 401(k)?

Yes. You can split contributions between the two, but the combined total cannot exceed the annual limit: $24,500 for 2026, or $32,500 with the age-50 catch-up ($35,750 for ages 60 to 63).

Are there income limits for contributing to a Roth 401(k)?

No. Unlike a Roth IRA, a Roth 401(k) has no income limit, so high earners can contribute the full amount.

Do I have to take required minimum distributions from a Roth 401(k)?

No. As of 2024, a Roth 401(k) is not subject to lifetime RMDs, the same as a Roth IRA. You no longer need to roll it into a Roth IRA to avoid them.

Can I withdraw from my Roth 401(k) before retirement?

You can, but it usually costs you. A non-qualified early withdrawal is prorated between contributions and earnings, and the earnings portion is taxed plus a 10% penalty unless an exception applies (such as disability, or leaving your job in or after the year you turn 55). The first-time-homebuyer penalty exception applies to IRAs, not 401(k)s.

How do I decide between a Roth 401(k) and a traditional 401(k)?

If you expect a similar or higher tax rate in retirement, or you value tax-free income and no RMDs, a Roth 401(k) is often the better choice. If you expect a lower rate later and want to cut your taxable income now, a traditional 401(k) fits better. Many people use both.

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