Traditional vs Roth 401(k): How the Tax Treatment Differs (2026)

IRS-governed — employer plan

Traditional 401(k)

Pre-tax now, taxed later — lowers this year's taxable income.

• 2026 contribution limit: $24,500
• Tax now: Deferred
• Tax at withdrawal: Ordinary income
• Catch-up (50+): $8,000

Pros

• Lowers your taxable income in the contribution year
• Useful if you expect a lower tax bracket in retirement
• Same $24,500 deferral limit as the Roth side (IRS 2026)

See the IRS Roth comparison chart →

IRS-governed — employer plan

Roth 401(k)

After-tax now, tax-free later — qualified withdrawals come out untaxed.

• 2026 contribution limit: $24,500
• Tax now: Paid
• Tax at withdrawal: Tax-free
• No income limit: Correct

Pros

• Qualified withdrawals — including all growth — are tax-free
• No income limit to contribute (unlike a Roth IRA)
• Useful if you expect higher future tax rates

See the IRS Roth comparison chart →

The tax timing. Traditional 401(k) contributions are pre-tax — you reduce taxable income now and pay taxes on withdrawals in retirement. Roth 401(k) contributions are after-tax — you pay taxes now and qualified withdrawals in retirement (after age 59½ and 5+ years) are completely tax-free. Both have the same contribution limit ($23,000 in 2024, $30,500 if 50+). Source: IRS at irs.gov.

The standard framework: if you expect your tax rate in retirement to be higher than today, Roth wins (pay low taxes now, withdraw tax-free later). If you expect your tax rate in retirement to be lower, traditional wins (defer taxes at your current higher rate). For younger workers earlier in their careers with lower current income, Roth is commonly favored. For high earners in peak earning years, traditional often wins. This is a structural comparison, not tax advice — consult a qualified advisor for your situation. Source: IRS Publication 590-A at irs.gov.

Yes, if your employer plan offers both. The combined contribution across both cannot exceed the annual limit ($23,000 in 2024, $30,500 if 50+). You can split contributions in any ratio between the two. Unlike IRA accounts, Roth 401(k) contributions have no income limits — high earners who are phased out of Roth IRA contributions can still contribute to a Roth 401(k). Source: IRS.gov.

Traditional 401(k) accounts are subject to Required Minimum Distributions (RMDs) starting at age 73 under current law (SECURE 2.0). Roth 401(k) accounts were previously subject to RMDs, but SECURE 2.0 eliminated RMDs from Roth 401(k)s starting in 2024 — aligning them with Roth IRAs, which have no RMDs during the owner's lifetime. This makes the Roth 401(k) a stronger estate planning tool for those who don't need to draw down retirement savings. Source: IRS.gov SECURE 2.0 guidance.