Overview
Tax reforms enacted in 2001 authorized Roth 401(k) plans beginning in tax year 2006. The Pension Protection Act of 2006 made them permanent. These accounts are similar to Roth IRAs: after-tax dollars are contributed, investment income grows tax-sheltered, and qualifying withdrawals are taken tax-free.
Technically, Roth 401(k)s are not separate stand-alone plans. They are a special accounting feature within an existing 401(k) plan — a designated Roth account (DRA) that separately tracks after-tax elective contributions and earnings on those contributions.
| Feature | Roth 401(k) | Roth IRA |
|---|---|---|
| Income limit to contribute | None | Yes (phase-out applies) |
| 2026 contribution limit | $24,500 (shared with traditional 401k) | $7,000 |
| Employer contributions | Permitted (go to pre-tax account) | Not applicable |
| RMDs required | No (SECURE Act 2.0, effective 2024) | No |
| Tax-free distribution — homebuyers | No | Yes (first-time homebuyers) |
| Non-qualified distributions | Pro-rata taxation (earnings portion) | FIFO — contributions first, then earnings |
| Rollover to Roth IRA | Yes — holding period restarts | N/A |
| Rollover from Roth IRA | No | N/A |
Participation
Although the tax code permits Roth 401(k) plans, it does not require employers to offer them. Each employer decides whether to offer the Roth feature. If an employer offers Roth accounts to any employee, it must offer them to all eligible employees. Employers may offer only a traditional 401(k), but may not offer solely a Roth 401(k) — a traditional option must always accompany a Roth feature.
Eligibility requirements are the same as for any 401(k):
- Age 21 or older
- At least one year of service
- Not covered by a collective bargaining agreement
Unlike Roth IRAs — which exclude high-income earners through phase-out thresholds — Roth 401(k) plans are available to all eligible employees regardless of income. A highly compensated employee earning $500,000 may contribute to a Roth 401(k) with no income limitation.
Contributions
The same annual elective deferral limits apply to both traditional and Roth 401(k) contributions. An employee’s total elective deferrals to both accounts combined cannot exceed $24,500 in 2026 (plus catch-up of $8,000 for age 50+, or $11,250 super catch-up for age 60–63).
The key difference is the tax treatment of the contribution:
- Traditional 401(k): Contributions are made before-tax. The employer deposits the elective contribution and the employee excludes it from taxable income on the annual return.
- Roth 401(k): Contributions are made after-tax. The employer withholds payroll taxes before depositing, and the employee includes the amount in taxable income for the year.
Once contributions are allocated to a Roth 401(k), they cannot be converted back to a traditional 401(k). Employees may change whether future contributions are Roth or traditional, but prior contributions cannot be undone (unlike Roth IRAs, which previously allowed some recharacterization).
Employer matching contributions, nonelective contributions, and plan forfeitures allocated to a Roth participant’s account are placed in the pre-tax account, not the Roth account. Employer contributions are always pre-tax regardless of whether the employee elected Roth deferrals.
Employees must be given the opportunity to change the Roth/traditional status of their contributions at least once per year. Plans with automatic enrollment must disclose whether automatic contributions default to pre-tax or Roth status.
Plans with the Roth feature must maintain a separate account for each employee to hold after-tax elective contributions and the earnings on those contributions. This creates two parallel accounts for each participating employee:
- Roth account: After-tax elective contributions + earnings
- Pre-tax account: Traditional elective contributions + all employer contributions + earnings
This dual-account requirement increases administrative complexity and cost, which may lead some employers to choose not to offer the Roth feature.
Distributions
The primary advantage of a Roth 401(k) is tax-free distributions. To qualify for tax-free treatment, a distribution must be a qualified distribution, meaning both of the following are satisfied:
- The account has been open for at least five consecutive tax years, and
- The employee is age 59½ or older, or is disabled or has died
The five-year holding period begins on the first day of the tax year in which the employee made the first Roth contribution (January 1 of that year for calendar-year taxpayers).
Margo, age 56, makes her first Roth 401(k) contribution on December 14, 2026. Her five-year holding period begins January 1, 2026 and ends December 31, 2030.
Assume Margo continues contributing $3,000/year for the next nine years. In 2036, at age 65, she withdraws the entire balance of $59,000 ($27,000 contributions + $32,000 earnings). She satisfies both conditions: the 5-year period has passed, and she is over 59½. The entire distribution is tax-free.
If a withdrawal is taken before age 59½ (or before death/disability), or before the five-year holding period expires, the distribution is non-qualified — meaning the earnings portion is taxable. Because Roth contributions were already taxed, only the proportionate share of earnings is included in income.
The taxable earnings percentage = earnings in Roth account ÷ total value of Roth account.
A participant, age 45, takes a $4,000 non-qualified withdrawal from their Roth 401(k) account. The account consists of $15,000 in after-tax Roth contributions and $5,000 in tax-deferred earnings (total value: $20,000).
Taxable earnings ratio: $5,000 ÷ $20,000 = 25%
Taxable portion of $4,000 withdrawal: 25% × $4,000 = $1,000 (ordinary income)
Tax-free return of contributions: $3,000
Important contrast with Roth IRA: If this were a Roth IRA, the first $15,000 withdrawn would be tax-free (FIFO — contributions come out first), and only the last $5,000 would be taxable. The Roth 401(k) pro-rata method is less favorable for partial withdrawals.
A 401(k) plan with a Roth feature may allow hardship distributions from the Roth account. However, hardship distributions do not receive favorable tax treatment — unless the account has been open five tax years and the employee is age 59½, the distribution is non-qualified and subject to pro-rata taxation.
If the employer’s plan permits loans, participants may borrow from the Roth 401(k) account, subject to the same rules as any 401(k) loan (lesser of $50,000 or 50% of vested balance; 5-year repayment; quarterly amortization).
Rollovers
Roth 401(k) assets may be rolled over to:
- Another employer’s Roth 401(k) (if that plan accepts Roth rollovers), or
- A Roth IRA
Under no circumstances may Roth IRA assets be rolled into a Roth 401(k).
Two methods are available:
- Employee distribution: The employee receives the distribution and rolls over only the tax-free portion to the new Roth 401(k) within 60 days. The taxable portion may not be rolled into the Roth account.
- Direct custodian-to-custodian transfer: The entire balance (both tax-free and taxable portions) is transferred directly. This is the preferred method. The five-year holding period of the original account carries over — the “age” of the account is preserved.
When Roth 401(k) assets are rolled to a Roth IRA, the holding period of the Roth 401(k) is disregarded. The five-year clock is based on when the Roth IRA was first established — which may be an advantage or disadvantage depending on circumstances.
Scenario A: Layton has participated in a Roth 401(k) for two years but has had a Roth IRA for more than five years. He rolls his Roth 401(k) into the existing Roth IRA. Because the IRA already satisfies the five-year test, Layton — being over 59½ — can take tax-free distributions immediately from the IRA.
Scenario B: Layton has a Roth 401(k) but no existing Roth IRA. If he establishes a new Roth IRA to receive the rollover, he starts a fresh five-year waiting period before qualified, tax-free distributions can be taken from that IRA.
Tax-sheltered annuities for public school teachers and nonprofit employees (403(b) plans) may also offer a Roth-style account. Roth 401(k) assets may be rolled to a Roth 403(b) or vice versa. Both may be rolled to a Roth IRA — but a Roth IRA’s assets cannot be rolled into either a Roth 401(k) or Roth 403(b).