How a Roth 401(k) works
A Roth 401(k) is not a separate plan. It is a designated Roth account, a separately tracked part of your employer’s 401(k), and the same feature exists in 403(b) and governmental 457(b) plans. When you elect Roth, the deferral stays in your taxable wages and is withheld on like any other pay, then deposited into the Roth account. The election is irrevocable: a Roth deferral can never be switched back to pre-tax. It is also different from after-tax 401(k) contributions, whose earnings are taxed when they come out.
A plan that offers Roth must also offer pre-tax deferrals, and you can split each paycheck between the two in any proportion. Both follow the same plan rules, so the Roth side is no easier to tap while you work: hardship withdrawals and loans follow the plan’s terms, and a nonqualified payout carries a pro-rata share of taxable earnings.
Roth 401(k) contributions have been allowed since 2006. Since SECURE 2.0, a plan may also let you take employer matching or nonelective money as Roth, but only once you are fully vested in it; that money is taxed as income for the year it is allocated to your account.
Roth 401(k) rules and limits for 2026
The Roth side has no limit of its own: Roth and pre-tax deferrals together must fit the annual deferral limit, while employer money counts against the plan’s separate total-additions ceiling instead. What sets a Roth 401(k) apart from a Roth IRA is who can use it: there is no income test, so earners who are phased out of a Roth IRA can still save Roth money at work, in amounts more than three times the IRA limit.
- Deferral limit, pre-tax and Roth combined: $24,500 for 2026.
- Catch-up: $8,000 more from age 50, or $11,250 in the years you turn 60 through 63.
- Mandatory Roth catch-up: from 2026, if your prior-year FICA wages from this employer exceeded $150,000, any catch-up must be Roth.
- Income limit: none. Roth IRA contributions, by contrast, phase out at $153,000–$168,000 of modified AGI for single filers and $242,000–$252,000 for joint filers in 2026.
- Lifetime required minimum distributions: none since 2024, matching the Roth IRA.
- No spousal version: you cannot fund a Roth 401(k) for a spouse without pay, as you can with a spousal IRA.
Qualified withdrawals and the five-year rule
A withdrawal is qualified, and entirely tax-free, only when two tests are met. First, five taxable years must have passed since January 1 of the first year you made a Roth contribution to that plan. Second, you must be 59½ or older or disabled, or the payment must go to your beneficiary after your death. Unlike a Roth IRA, a Roth 401(k) has no first-home exception.
The clock runs per plan. A direct rollover from an earlier employer’s Roth account carries that account’s older start date with it. A rollover to a Roth IRA does not: there the Roth IRA’s own clock applies, so an IRA opened years earlier can make rolled-over money qualified sooner. The Roth five-year rule page compares every clock.
A nonqualified withdrawal is split pro rata between contributions, which come back tax-free, and earnings, which are taxed and may owe the 10% additional tax before 59½; the formula below does the split. In the IRS’s own illustration, $5,000 taken from an account holding $9,400 of contributions and $600 of earnings is $4,700 of contributions and $300 of taxable earnings. A Roth IRA treats you better here, because its regular contributions come out first.
Roth 401(k) vs. traditional 401(k)
The choice is a bet on tax rates. A pre-tax deferral saves tax at today’s marginal rate and is taxed at whatever rate applies when you withdraw. A Roth deferral does the reverse. If the two rates are equal, the after-tax results are identical, as the example below shows; Roth wins when your rate later is higher, and pre-tax wins when it is lower.
Several things tilt the bet. Early-career workers in low brackets, people expecting a large pension or large RMDs, and anyone planning to retire in a higher-tax state often lean Roth. Peak earners, and people who expect several low-income years before claiming Social Security that could be used for a Roth conversion, often lean pre-tax. Because a Roth dollar is already net of tax, the same $24,500 deferral also shelters more future spending power as Roth than as pre-tax.
Many savers split contributions to build tax diversification: holding pre-tax, Roth and taxable money lets you choose each year which kind of income to take.
Illustrative numbers
Same take-home cost, three possible tax rates later
- W
- Amount withdrawn from the Roth 401(k)
- E
- Earnings in the Roth account
- C
- Your Roth contributions, which are already taxed
A qualified withdrawal is tax-free in full; before 59½ the taxable part may also owe the 10% additional tax.
Pay set aside, 24% marginal rate today$10,000
Roth 401(k) deposit after tax$7,600
Traditional 401(k) deposit$10,000
Growth factor, 30 years at 6% a year× 5.743
Roth balance, all tax-free$43,651
Traditional balance after tax at 22% / 24% / 32%$44,799 / $43,651 / $39,056
Both choices cost the same $7,600 of take-home pay today. If withdrawals are taxed at 24%, they finish level; a 22% rate later favors the traditional account by about $1,150, and a 32% rate favors the Roth by about $4,600. The decision turns on your future tax bracket, not on the balance a statement shows.
At a glance
Roth 401(k) vs. traditional 401(k) vs. Roth IRA (2026)
| Feature | Roth 401(k) | Traditional 401(k) | Roth IRA |
|---|---|---|---|
| Contributions made with | After-tax pay | Pre-tax pay | After-tax money |
| Qualified withdrawals | Tax-free | Taxed as ordinary income | Tax-free |
| 2026 limit | $24,500, shared with pre-tax | $24,500, shared with Roth | $7,500 |
| Income limit to contribute | None | None | Phases out from $153,000 single, $242,000 joint |
| Five-year clock | Separate for each plan | Not applicable | One clock for all your Roth IRAs |
| Early access to contributions | Only pro rata with earnings | Whole withdrawal taxable | Contributions first, tax- and penalty-free |
| Lifetime RMDs | None since 2024 | Yes, from 73 or 75 | None |
| Employer match | Pre-tax unless you elect Roth on vested money | Pre-tax | None |
Put it in your plan
Roth 401(k) in MoneyWhatIf
MoneyWhatIf holds a Roth 401(k) as its own account, separate from pre-tax 401(k) money. Roth and pre-tax workplace deferrals share one year’s contribution room, but only the pre-tax part lowers ordinary income. Headline net worth counts a Roth dollar and a pre-tax dollar the same; taxable net worth estimates what would remain after tax if everything were withdrawn or sold in one year. The estate view places Roth 401(k) balances in the Roth category. The 2026 rule that some higher earners’ catch-ups must be Roth is not modeled.
Common questions
Roth 401(k) FAQs
What are the downsides of a Roth 401(k)?
The main one is paying tax now: a Roth deferral shrinks this year’s take-home pay more than the same pre-tax deferral, and the payoff depends on a future tax rate nobody knows. A withdrawal that is not yet qualified is taxed pro rata on earnings, with no contributions-first rule and no first-home exception. An all-Roth saver also gives up pre-tax money that could be withdrawn later in low-bracket years.
Can I contribute to a Roth 401(k) and a Roth IRA in the same year?
Yes. The limits are separate: for 2026 you can defer up to $24,500 to your 401(k), pre-tax and Roth combined, and also put $7,500 into IRAs, plus catch-ups from age 50. The Roth IRA keeps its income limits, so a single filer with modified AGI of $168,000 or more cannot contribute directly, though a backdoor Roth IRA may still be possible.
Does my employer match go into my Roth 401(k)?
Usually not. A match on Roth deferrals has traditionally gone into the pre-tax side of the plan, so it is taxed when you withdraw it. Since SECURE 2.0, a plan may let you designate vested matching or nonelective contributions as Roth. If yours does, that money is taxable income for the year it is allocated but nothing is withheld, so you may need to raise your withholding. The 401(k) match page covers the details.
What happens to a Roth 401(k) when I leave my job?
You can leave it in the plan if allowed, move it by direct rollover to a new employer’s Roth account, or roll it to a Roth IRA. A direct rollover to another plan keeps your original five-year start date. A rollover to a Roth IRA follows that IRA’s own five-year clock instead. Avoid taking a check and redepositing it: within 60 days only the taxable earnings can go to another plan, while the contribution basis can go only to a Roth IRA.
Can I convert pre-tax 401(k) money to Roth inside the plan?
Yes, if the plan offers in-plan Roth rollovers. You can move vested pre-tax deferrals, matching and other money into the plan’s Roth account. The converted amount, minus any after-tax basis, is taxable income that year, no withholding is required on a direct transfer, and it cannot be undone. It works much like a Roth conversion of an IRA, and taking converted money out within five years, before 59½, can trigger the 10% additional tax.