401(k) Contribution Limits Changed This Year and Here Is What You Should Do Now

With the IRS raising the 401(k) employee deferral limit to $24,500 for 2026, up from $23,500 in 2025, a $1,000 increase can feel routine. It is not. Two other limit changes deserve serious attention this year, starting with a SECURE 2.0 super catch-up provision that opens the most generous pre-retirement savings window Congress has ever written into law.

The Three Numbers That Actually Matter in 2026

The $1,000 bump in the base deferral limit is real money over time. Compounding that extra $1,000 annually at 7% across 10 years adds roughly $13,800 in retirement assets. Useful, but still not the headline.

The catch-up contribution for workers aged 50 and older rose from $7,500 in 2025 to $8,000 in 2026, bringing the total deferral ceiling for over-50 workers to $32,500. Maxing that combined limit at 7% over a decade produces approximately $449,000. A critical new rule also takes effect for the first time in 2026: if your 2025 FICA wages exceeded $150,000, the IRS now requires catch-up dollars to go into a Roth (after-tax) account. You give up the immediate deduction, but every dollar of growth and every qualified withdrawal comes out entirely tax-free. One practical warning: if your employer’s plan does not yet offer a Roth option, you may be unable to make catch-up contributions at all until the plan is updated.

The real headline is the SECURE 2.0 super catch-up for workers aged 60 through 63. For 2026, that limit is $11,250, replacing the standard catch-up for those four years. Combined with the base deferral, someone in that window can contribute up to $35,750 this year. Ten years of maxing it out at 7% yields roughly $494,000, about $45,000 more than the standard 50-plus path over the same period.

If you turned 60, 61, 62, or 63 this year and are not hitting $35,750, you are leaving the most generous contribution window Congress has ever created for pre-retirees on the table.

The Ceiling Most High Earners Have Never Heard Of

The total additions limit under IRC Section 415(c) rose from $70,000 in 2025 to $72,000 in 2026. This ceiling caps all contributions to a defined contribution plan in a single year: employee deferrals, employer contributions, and after-tax contributions combined.

For most W-2 employees, the 415(c) limit is invisible because their employer match does not push them anywhere near it. For self-employed individuals, business owners with solo 401(k)s, or employees at firms that allow after-tax contributions, this is the real ceiling to watch. A business owner who contributes $24,500 as an employee and layers on a profit-sharing contribution of $47,500 hits exactly $72,000. Every dollar above that creates a risk of plan disqualification.

The mega backdoor Roth works within this framework: contribute after-tax dollars up to the $72,000 total, then convert those funds to Roth. Most plan documents do not permit it, so confirm whether your plan allows after-tax contributions, in-service withdrawals, or in-plan Roth conversions before assuming this strategy is available to you.

The Tax Trap Hiding Inside a Larger Balance

Every dollar deferred into a traditional 401(k) today will be taxed as ordinary income when withdrawn. For someone on Medicare, those withdrawals also factor into the income calculation that determines IRMAA surcharges added to Medicare Part B and Part D premiums.

In 2026, the standard Part B monthly premium is $202.90. Cross the first IRMAA threshold at $109,000 in modified adjusted gross income for single filers and that premium jumps to $284.10 per month, nearly $975 more per year. The surcharge functions as a cliff: a single dollar of income above the line triggers the full additional charge. Because the SSA bases its 2026 IRMAA determination on your 2024 tax return, a large 401(k) withdrawal or Roth conversion made in 2026 will surface instead in your 2028 Medicare premiums. Planning two years ahead is not optional; it is the minimum.

A retiree in the 22% federal bracket who inadvertently crosses the IRMAA threshold can face a combined effective marginal rate approaching 40% on the dollars that push them over. Whether to maximize traditional 401(k) contributions or redirect savings to a Roth account involves both future tax rates and future Medicare costs.

Who Should Fill the Gap and Who Should Redirect

1. Ages 60 to 63 with earned income and a balance below $1 million: Max the super catch-up first. The $35,750 ceiling disappears after age 63, and the tax deferral on that amount compounds for decades. This window is time-limited, and the math strongly favors using it while it lasts.
2. High earners with large traditional 401(k) balances already on track to generate significant RMDs: Additional deferrals may be adding fuel to a future tax fire. If projected RMDs at age 73 will push you into the 24% bracket or above the IRMAA threshold, redirecting new savings to a Roth IRA or Roth 401(k) reduces that future exposure. The 2026 Roth IRA contribution limit is $7,500, or $8,600 for savers aged 50 and older once the $1,100 catch-up is included.
3. Business owners and solo 401(k) holders: Confirm whether your plan allows after-tax contributions. The 415(c) limit of $72,000 creates room to contribute well beyond the employee deferral cap. If your plan document permits it, the mega backdoor Roth is the most efficient tax-free compounding vehicle available outside of a health savings account. If your combined income already exceeds the first IRMAA threshold at $109,000, the tax planning around these decisions alone justifies a session with a fee-only advisor.

Editor’s note: This revision confirms that the Roth catch-up mandate FICA wage threshold for 2026 is $150,000 (the inflation-indexed figure, up from the $145,000 originally written into the SECURE 2.0 statute), and adds context that employees whose plans lack a Roth option may lose catch-up contribution eligibility entirely until their plan is amended. The IRMAA cliff mechanic, the 2026 Part B premium of $202.90, and the first-tier surcharge bringing the premium to $284.10 are all confirmed against current CMS and IRS figures.

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