Yes, a 401(k) can be a Roth. Federal law lets employers add a designated Roth account inside a regular 401(k) plan, and most large employers now do. When your plan offers it, you can direct some or all of your salary deferrals into the Roth bucket instead of the traditional pre-tax bucket, pay income tax on that money now, and take qualified withdrawals in retirement completely tax-free. The same plan can hold both a pre-tax balance and a Roth balance for the same person.
Check Whether Your Plan Offers a Roth Option
The law permits Roth contributions inside a 401(k), but it does not force employers to offer them.1Office of the Law Revision Counsel. 26 USC 402A – Optional Treatment of Elective Deferrals as Roth Contributions Your company has to amend its plan document to add a “qualified Roth contribution program” before any employee can put money into a Roth account. Without that amendment, the plan is traditional-only for everyone.
The quickest way to find out is to ask HR for the Summary Plan Description. Plan administrators are required to provide this document, and it lists every contribution type available under the plan, along with the eligibility rules.2Internal Revenue Service. 401(k) Resource Guide – Plan Participants – Summary Plan Description Most employers also post it on an internal benefits portal. If Roth contributions are not listed, your plan simply does not offer one yet.
How Roth 401(k) Money Is Taxed
Roth 401(k) contributions come out of pay you have already paid income tax on. There is no upfront tax deduction the way there is with pre-tax deferrals.1Office of the Law Revision Counsel. 26 USC 402A – Optional Treatment of Elective Deferrals as Roth Contributions The benefit shows up later: your contributions and every dollar of investment earnings can be withdrawn tax-free, provided the withdrawal is “qualified.”
A qualified distribution has to clear two tests. At least five tax years must have passed since January 1 of the year you made your first Roth contribution to that plan. And you must be at least 59½, permanently disabled, or the money must go to a beneficiary after your death.3Internal Revenue Service. Retirement Plans FAQs on Designated Roth Accounts Meet both and the IRS does not touch a dollar of what comes out.
If you pull money out before both conditions are satisfied, your own contributions still come out tax-free because you already paid tax on them. The earnings portion, though, is taxed as ordinary income and typically hit with a 10% early withdrawal penalty.3Internal Revenue Service. Retirement Plans FAQs on Designated Roth Accounts
2026 Contribution Limits
The IRS caps elective deferrals to traditional and Roth 401(k) accounts under a single combined limit. For 2026 that limit is $24,500.4Internal Revenue Service. 401(k) Limit Increases to $24,500 for 2026, IRA Limit Increases to $7,500 Put $15,000 into the traditional side and you can put no more than $9,500 into the Roth side that year.
Participants aged 50 and older can add an $8,000 catch-up, for a personal ceiling of $32,500.4Internal Revenue Service. 401(k) Limit Increases to $24,500 for 2026, IRA Limit Increases to $7,500 A higher “super catch-up” of $11,250 applies if you are 60, 61, 62, or 63 during the year, taking the ceiling to $35,750. Once you add employer matching and any other employer contributions, the total from all sources cannot exceed $72,000 for 2026.5Internal Revenue Service. 2026 Amounts Relating to Retirement Plans and IRAs, as Adjusted for Changes in Cost-of-Living (Notice 2025-67)
Employer Matching Into a Roth Account
Since December 29, 2022, employers have had the option to deposit matching and nonelective contributions directly into the Roth side rather than the pre-tax side. This is a SECURE 2.0 change, and it applies only if your specific plan has adopted it.6Internal Revenue Service. SECURE 2.0 Act Changes Affect How Businesses Complete Forms W-2
The tradeoff is straightforward. If your employer puts matching dollars into your Roth bucket, you owe income tax on those contributions in the year they are made. Traditional matching defers that tax for decades; Roth matching flips the timeline. Before you elect this option, confirm you have enough cash flow to cover the additional current-year tax without pulling from the retirement account itself.
No Lifetime Required Minimum Distributions
This is one of the most useful recent improvements. Roth 401(k) accounts used to be subject to required minimum distributions starting at age 73, which forced money out of the account even when the owner did not need it. That rule no longer applies. Roth 401(k) accounts are now treated like Roth IRAs for RMD purposes: no distributions are required during the account owner’s lifetime.7Internal Revenue Service. Retirement Plan and IRA Required Minimum Distributions FAQs
The old workaround of rolling a Roth 401(k) into a Roth IRA just to escape RMDs is no longer necessary. You can leave the money in the employer plan and let it compound tax-free for as long as you live. Beneficiary RMD rules still apply after the account owner’s death.
Mandatory Roth Catch-Up for High Earners Starting in 2027
A SECURE 2.0 provision will require certain high earners to make all catch-up contributions on a Roth basis. It applies to catch-up contributions in tax years beginning after December 31, 2026, so 2027 is the first year it takes effect.8Internal Revenue Service. Treasury, IRS Issue Final Regulations on New Roth Catch-Up Rule, Other SECURE 2.0 Act Provisions If your prior-year FICA wages exceeded $145,000 (indexed for inflation), you lose the option to make pre-tax catch-up contributions. Regular deferrals up to $24,500 can still go pre-tax; every catch-up dollar must be Roth.
Plans are allowed to implement the requirement early using a good-faith interpretation of the statute.8Internal Revenue Service. Treasury, IRS Issue Final Regulations on New Roth Catch-Up Rule, Other SECURE 2.0 Act Provisions If you earn above the threshold and are 50 or older, expect a notice from your plan administrator, and consider how the switch will affect your paycheck and your tax planning.
Converting Existing Pre-Tax 401(k) Money to Roth
An in-plan Roth conversion (sometimes called an in-plan Roth rollover) moves existing pre-tax balances into your Roth bucket inside the same plan. Not every plan permits it, so the first step is to confirm with your plan administrator that the plan document specifically allows in-plan Roth rollovers. If it does not, the only conversion path is a rollover out to a Roth IRA, which is a separate process with different rules.
The entire converted amount counts as taxable income in the year of the conversion. A large conversion can push you into a higher bracket, create an obligation to make estimated tax payments, or raise other income-linked figures like Medicare premiums. Many people split conversions into smaller amounts over several years for that reason.
Your plan administrator will have an election form for the conversion. Once processed, your traditional balance drops and your Roth sub-account rises by the same amount, and the plan issues a Form 1099-R reporting the converted amount as a taxable distribution for that year.9Internal Revenue Service. Instructions for Forms 1099-R and 5498 (2025) The money never actually leaves the plan; the IRS just treats the conversion as a taxable event. The conversion has to be completed by December 31 to count for the current tax year, so leave enough runway for processing rather than submitting in late December.
Paying the Conversion Tax
In-plan conversions do not allow tax withholding from the converted amount, because the money never leaves the plan.10The Thrift Savings Plan (TSP). Roth In-Plan Conversions You cannot use part of the conversion itself to cover the tax bill. The cash has to come from somewhere else: a savings account, a brokerage account, or extra paycheck withholding on your regular pay.
Convert $50,000 at a 24% marginal federal rate and you are looking at roughly $12,000 in additional federal tax, plus any state income tax. For a large conversion, consider making quarterly estimated tax payments rather than waiting until you file. Underpayment penalties kick in when you owe more than $1,000 at filing and have not paid at least 90% of the current year’s liability through withholding or estimates.
The Separate Five-Year Rule for Conversions
Each in-plan Roth conversion carries its own five-year clock, distinct from the five-year rule that governs regular Roth contributions. If the plan distributes any part of an in-plan Roth rollover within five tax years of the conversion, the taxable portion of that distribution is subject to the 10% early withdrawal penalty unless an exception applies.3Internal Revenue Service. Retirement Plans FAQs on Designated Roth Accounts The rule exists to stop people from converting and immediately withdrawing to escape the penalty on pre-tax money.
The practical takeaway: do not convert money you might need in the next five years. Conversions work best for balances you intend to leave alone until retirement. If you are close to needing the funds, the recapture penalty can erase much of the tax benefit you were reaching for.