The single biggest design shift inside the American 401(k) this decade is about taxes, more than fees, target-date funds, or auto-escalation. According to Vanguard’s 2025 How America Saves report, 86% of plans now offer a Roth contribution option, up from 74% in 2020. Among participants whose plans offered it, 18% elected the Roth option in 2024, an all-time high, up from 12% in 2019. The traditional pre-tax 401(k) is no longer the only default, and in 2026, federal law is pushing even more employers in the same direction.
What “Rothification” Actually Means
A traditional 401(k) lets workers defer income taxes today and pay them in retirement when withdrawals begin. A Roth 401(k) flips that arrangement. Contributions are made with after-tax dollars, and qualified withdrawals, including all investment growth, come out completely tax-free. The core trade-off is straightforward: pay a known tax rate now, or pay an unknown future rate later.
Vanguard’s data captures how quickly that calculus has shifted. Among participants in larger plans, 96% are now offered Roth as a feature, making it close to universal for workers at mid-size and large employers. The six-percentage-point jump in adoption, from 12% of participants in 2019 to 18% in 2024, reflects both broader access and a growing awareness of where future tax rates might be headed. Separate from regular contributions, 36% of plans now also offer Roth in-plan conversions, which allow workers to shift existing pre-tax balances into a Roth account within the same plan, and 10% of plans make that conversion automatic.
Why the Tax Calculus Is Changing Now
The plan data supplies useful context. Hardship withdrawals hit 4.8% of participants in 2024, up from 3.6% in 2023, a sign that many household budgets are under pressure. At the same time, the average participant deferral rate reached an all-time high of 7.7% in 2024, with a median of 6.8%. When employer contributions are included, total contribution rates averaged 12.0%, putting a typical saver near the lower end of Vanguard’s own recommended 12% to 15% savings target. When workers are already stretching to save, the tax treatment of every dollar they set aside becomes a sharper question.
The regulatory backdrop is adding urgency. Under the SECURE 2.0 Act, beginning January 1, 2026, participants aged 50 and older who earned more than $150,000 in FICA wages from their employer in the prior year must make all catch-up contributions on a Roth basis. For plans that do not currently offer a Roth feature, that rule creates a hard choice: add Roth or lose the ability to accept catch-up contributions from higher-earning employees entirely. That compliance pressure is expected to push Roth availability even higher across the industry.
Plan Design Did Most of the Work
The broader Roth shift happened largely because plan sponsors changed the menu. The 86% availability figure is up from 74% five years ago, and among plans with at least 5,000 participants, 95% now offer the feature. Automatic enrollment has amplified the effect. Now in place at 61% of plans (up from just 10% in 2006), auto-enrollment drives participation rates to 94% in the plans that use it, compared to 64% for voluntary-enrollment plans. When Roth appears as an active contribution type inside that kind of high-participation environment, more workers encounter it as a real choice rather than a buried menu option.
Who Tends to Choose Roth
The 18% who elect Roth skew younger and higher-income, according to Vanguard’s demographic breakdown. Among participants under 25, 17% chose Roth when their plan offered it. In the $100,000 to $149,999 income bracket, 24% elected the option, as did 21% of those earning $150,000 or more. The pattern is consistent with workers who expect their current tax bracket to be lower than their eventual retirement bracket, or who simply want tax diversification across account types. That flexibility, holding both pre-tax and Roth balances simultaneously, gives retirees more control over which dollars they draw first and how much ordinary income they report in any given year.
What to Watch Next
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The SECURE 2.0 mandatory Roth catch-up rule, now in effect for 2026, will push plan sponsors who have not yet added a Roth feature to act quickly or lose catch-up eligibility for high earners.
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Many plans allow a split between traditional and Roth contributions, letting participants hedge the tax-rate question without committing entirely to one treatment.
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The 12.0% total contribution average (employee plus employer) now sits at the floor of Vanguard’s recommended savings range, a meaningful benchmark for workers assessing whether their deferral rate is on track.
Editor’s note: This update adds the SECURE 2.0 Act’s mandatory Roth catch-up contribution rule, effective January 1, 2026, for workers aged 50 and older who earned more than $150,000 in FICA wages in the prior year, and incorporates Vanguard’s finding that 36% of plans now offer Roth in-plan conversions and that 10% make those conversions automatic.
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