Higher 401(k) Catch-Up Tax Bill Set for 2026 If You Made Over $150,000 in 2025

If you earned more than $150,000 on your 2025 W-2, your 401(k) catch-up contributions in 2026 will cost more in taxes than they do today — and you won’t get a choice. Starting January 1, 2026, workers who exceeded that income threshold must make all catch-up contributions as designated Roth, meaning those dollars no longer reduce taxable income in the year they’re contributed.

The rule, mandated by Section 603 of SECURE 2.0 and codified at IRC § 414(v)(7), uses a lookback on prior-year wages. The statutory floor is $145,000, but IRS Notice 2025-67 indexes that figure in $5,000 increments, setting the 2025 threshold at $150,000. That means a worker who earned $160,000 in 2025 due to a bonus or commission spike will face Roth treatment in 2026 even if their current-year salary drops to $130,000.

In 2026, the base 401(k) deferral limit is $24,500. Workers 50 and older can add $8,000 in catch-up contributions, bringing their total to $32,500. Those aged 60 through 63 qualify for a $11,250 “super catch-up,” allowing $35,750 in total contributions. For anyone above the wage threshold, every dollar of that catch-up must go into a Roth account.

For a worker in the 24% tax bracket — single filers earning between $105,701 and $201,775 in 2026 — an $8,000 Roth catch-up means $1,920 in additional taxes compared to a pre-tax contribution. The super catch-up adds $2,700 in tax cost at the same rate.

The trade-off is long-term: Roth contributions grow tax-free and do not count toward modified adjusted gross income (MAGI) in retirement. That can prevent large pre-tax balances from triggering a cascade of costs later, including required minimum distributions (RMDs), taxation of Social Security benefits, and Medicare Part B surcharges.

In 2026, IRMAA surcharges begin at $109,000 MAGI for single filers and $218,000 for married couples filing jointly. Surcharges range from $81 to $487 per month, depending on income. A retiree whose RMDs push them into the first tier pays an extra $972 annually — a cost that could be avoided with Roth distributions, which are excluded from MAGI.

Workers expecting high retirement tax rates due to pensions, large pre-tax balances, or high Social Security benefits may benefit from the forced shift. Those expecting lower rates will pay taxes earlier on money they would have preferred to defer.

Employers without a designated Roth 401(k) option face a compliance hurdle. The final regulations require plan administrators to enforce Roth treatment — and if a plan lacks the infrastructure, it cannot accept catch-up contributions from affected employees. A 58-year-old earning above the threshold at such a company could lose access to the full $8,000 catch-up until the plan updates its systems.