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

If your employer offers both a Traditional and a Roth version of your 401(k), you’ll need to decide how to split your contributions between them — or which one to use exclusively. The decision mirrors the Roth vs. Traditional IRA choice, applied to your workplace retirement plan.

The core difference

• Traditional 401(k): Contributions are made before tax, reducing your taxable income in the year you contribute. Your money grows tax-deferred, and you pay ordinary income tax on withdrawals in retirement.
• Roth 401(k): Contributions are made after tax (no upfront deduction). Your money grows tax-free, and qualified withdrawals in retirement are tax-free.

An important distinction from a Roth IRA

Unlike a Roth IRA, a Roth 401(k) has no income limits restricting who can contribute. This makes the Roth 401(k) a useful option for higher earners who might otherwise be phased out of contributing directly to a Roth IRA.

How to think about the choice

As with the IRA version of this decision, the central question is: do you expect to be in a higher or lower tax bracket in retirement than you are now?

• If you expect a lower tax bracket in retirement, the Traditional 401(k)’s upfront deduction may be more valuable, since you defer tax to a year when your rate is likely lower.
• If you expect a similar or higher tax bracket in retirement — common for younger workers early in their careers with room for income growth — the Roth 401(k) can be more valuable, since you lock in today’s tax rate rather than paying at a potentially higher future rate.

The employer match: a special rule to know

If your employer offers a matching contribution, that match is generally deposited into a Traditional (pre-tax) account regardless of whether your own contributions go to the Roth or Traditional side — a detail that surprises some people. This means even an employee contributing 100% to a Roth 401(k) will typically still end up with some pre-tax money in the plan from the employer match, which will be taxed upon withdrawal in retirement.

Required withdrawals

Unlike a Roth IRA, a Roth 401(k) has historically been subject to Required Minimum Distributions (RMDs) starting at a certain age — though rules in this area have changed over time to more closely align Roth 401(k)s with Roth IRAs on this point. Because retirement account rules are updated periodically, it’s worth checking current requirements directly rather than assuming older information still applies.

Splitting contributions between both

Since many plans allow it, some people choose to split contributions between Traditional and Roth 401(k) options — a form of “tax diversification” that hedges against uncertainty about future tax rates, similar to the reasoning covered in our Roth vs. Traditional IRA guide.

A simplified example

Suppose you contribute $500 per paycheck to your 401(k):

• All Traditional: The full $500 reduces your taxable income now; you’ll pay ordinary income tax on the entire withdrawal (contributions plus growth) in retirement.
• All Roth: You pay tax on the $500 now (no deduction); qualified withdrawals of both contributions and growth are tax-free in retirement.
• Split 50/50: $250 reduces your taxable income now, while the other $250 is taxed now but grows tax-free — a middle-ground approach if you’re genuinely unsure about your future tax situation.

Key takeaways

• A Roth 401(k) works like a Roth IRA (no upfront deduction, tax-free qualified withdrawals) but with no income limits on who can contribute.
• Employer matching contributions are generally deposited pre-tax, regardless of which type you personally contribute to.
• The choice largely comes down to your expected tax bracket now versus in retirement — and splitting contributions is a reasonable hedge if you’re uncertain.

This article is for educational purposes only and isn’t personalized tax or financial advice — plan rules vary and change over time, so verify current details with your plan administrator or a tax professional. See our full disclaimer.