The choice between an employee deferral and a Roth deferral inside your 401(k) comes down to when you want to pay income tax on the money: a traditional (pre-tax) employee deferral cuts your taxable income now and gets taxed as ordinary income when you withdraw it, while a Roth deferral is taxed upfront and comes out tax-free in retirement if you meet the rules. Both use the same $24,500 combined cap in 2026, both live inside the same employer plan, and you can use both at once.1Internal Revenue Service. 401(k) Limit Increases to $24,500 for 2026, IRA Limit Increases to $7,500 The right pick depends on where you think your tax rate is going.
What Each Option Does to Your Paycheck
A traditional employee deferral comes out of pay before federal and state income tax is calculated. Earn $70,000, defer $10,000, and your W-2 shows $60,000 of taxable wages. You feel the benefit as a smaller tax bill this year.2Internal Revenue Service. 401(k) Plan Overview
A Roth deferral is the mirror image. The contribution comes out of already-taxed pay, so the same $70,000 earner deferring $10,000 to the Roth bucket still reports $70,000 in taxable wages. No deduction now.3Internal Revenue Service. Roth Account in Your Retirement Plan Your take-home pay is smaller for the same dollar contribution.
One thing that does not change between the two: Social Security and Medicare taxes hit the full contribution either way. A pre-tax deferral only avoids income tax withholding, not FICA.4Internal Revenue Service. Retirement Plan FAQs Regarding Contributions – Are Retirement Plan Contributions Subject to Withholding for FICA, Medicare, or Federal Income Tax
What Each Option Does at Withdrawal
Every dollar you eventually pull out of the traditional bucket, contributions and investment growth alike, is taxed as ordinary income. Federal rates run from 10 percent to 37 percent depending on your total income that year.5Internal Revenue Service. Federal Income Tax Rates and Brackets
Qualified Roth withdrawals are tax-free, including every dollar of growth. To qualify, the Roth account has to have been open for at least five tax years and you have to be at least 59½ (or disabled, or the distribution goes to a beneficiary after death).6Internal Revenue Service. Retirement Topics – Designated Roth Account
The five-year clock starts on January 1 of the first tax year you make any Roth contribution to the plan. A first Roth deferral in November 2026 starts the clock on January 1, 2026, and the account clears the five-year test at the start of 2031.7Internal Revenue Service. Retirement Plans FAQs on Designated Roth Accounts
Which One Is Better for Your Situation
The core question is whether your marginal tax rate in retirement will be higher or lower than it is today. If it will be lower, the traditional deferral wins because you skip tax at today’s higher rate and pay at tomorrow’s lower one. If it will be higher, Roth wins for the same reason in reverse. Nobody has certainty about future tax rates, and that uncertainty is itself a reasonable argument for splitting contributions.
A few situations push the answer one direction:
- Early career, low bracket. If you’re paying 12 percent now and might retire in the 22 or 24 percent bracket, paying tax now through Roth and pulling decades of growth out tax-free is a favorable trade.
- Peak earnings, few years from retirement. Sitting in the 32 or 37 percent bracket with a lower-income retirement in sight is what pre-tax deferrals are designed for. Take the deduction now, pay tax later at a lower rate.
- Long horizon. The longer the money has to compound, the more valuable tax-free growth becomes, and the more Roth pulls ahead.
- Substantial retirement income already baked in. Pensions, rental income, and Social Security can push retirement brackets higher than people expect. Roth withdrawals don’t add to that taxable stack.
Holding both buckets by the time you retire is its own advantage. You can pull from the traditional side up to the top of a low bracket, then draw the rest of what you need from the Roth side without pushing yourself into a higher one. That flexibility is hard to replicate with only one type of account.
2026 Contribution Limits Apply to the Combined Total
The $24,500 baseline limit for 2026 covers your traditional and Roth deferrals together, not each separately. Split $15,000 traditional and $9,500 Roth if you want; you cannot do $24,500 of each.1Internal Revenue Service. 401(k) Limit Increases to $24,500 for 2026, IRA Limit Increases to $7,500
Older workers get more room:
- Age 50 and older: an extra $8,000 catch-up, for a combined limit of $32,500.
- Ages 60 through 63: a higher $11,250 catch-up created by the SECURE 2.0 Act, for a combined limit of $35,750. At 64 you drop back to the standard $8,000.
These caps cover 401(k), 403(b), and governmental 457(b) plans.8Internal Revenue Service. Retirement Topics – 401(k) and Profit-Sharing Plan Contribution Limits Note that Roth deferrals inside a workplace plan have no income limit, unlike Roth IRAs. A $400,000 earner can make Roth 401(k) deferrals without any phase-out.
High Earners Lose the Choice on Catch-Up Contributions
Starting in 2026, if your prior-year FICA wages topped $150,000, your catch-up contributions must go in as Roth. Pre-tax catch-ups are off the table for you. This comes from Section 603 of the SECURE 2.0 Act.9Internal Revenue Service. Treasury, IRS Issue Final Regulations on New Roth Catch-Up Rule, Other SECURE 2.0 Act Provisions
Two things worth knowing about this rule. First, it only touches the catch-up portion. Your base $24,500 can still be traditional, Roth, or any mix regardless of income. Second, if your plan doesn’t offer a Roth option and you’re over the wage threshold, you may lose the ability to make catch-up contributions at all. The IRS has said good-faith compliance is enough for 2026, with full regulatory compliance required for plan years beginning in 2027. The $150,000 threshold is indexed for inflation.
Below the threshold, catch-up contributions remain a free choice between the two types.
Roth Has No Lifetime Required Minimum Distributions
Traditional pre-tax balances have to start paying out at age 73 (rising to 75 in 2033) whether you need the money or not. Missing a required minimum distribution triggers a 25 percent excise tax on the shortfall, dropping to 10 percent if you fix it within two years.10Internal Revenue Service. Retirement Plan and IRA Required Minimum Distributions FAQs
Roth balances inside 401(k) and 403(b) plans used to face the same forced schedule. The SECURE 2.0 Act ended that starting in 2024, so Roth money in an employer plan is no longer subject to RMDs during the account owner’s lifetime.11U.S. Senate Finance Committee. SECURE 2.0 Act of 2022 Section-by-Section For anyone who expects to retire with more than they need, or who wants to leave assets to heirs, that’s a real argument in Roth’s favor beyond the tax-rate math.
What About the Employer Match
The type of deferral you pick does not change where the match lands by default. Employer matching contributions have historically gone into a pre-tax bucket, taxed as ordinary income when you withdraw them, even if 100 percent of your own contributions went in as Roth.
The SECURE 2.0 Act now lets employers deposit the match directly into your Roth account instead. If your plan adopts this, the matched amount is taxable income in the year it’s contributed, and then grows and comes out tax-free.12Internal Revenue Service. SECURE 2.0 Act Changes Affect How Businesses Complete Forms W-2 Most plans haven’t adopted this yet, so assume a pre-tax match unless HR tells you otherwise.
One Rollover Trap to Know
Rolling a Roth 401(k) into a Roth IRA when you leave a job is tax-free as a direct rollover, but the five-year clock does not carry over. The Roth IRA runs on its own five-year timer measured from your first Roth IRA contribution.7Internal Revenue Service. Retirement Plans FAQs on Designated Roth Accounts Opening a Roth IRA now with even a token contribution starts that clock, so it’s already satisfied by the time you might roll workplace Roth money over years later. It’s one of the cheapest planning moves available.