When you max out your 401(k), payroll deductions stop automatically for the rest of the calendar year, and the money that had been flowing into your retirement account starts showing up in your paycheck as ordinary taxable wages. That is the mechanical answer. The financial answer is more interesting: depending on how your employer calculates its match and whether your plan offers extra savings features, hitting the limit early can either be a non-event or cost you thousands of dollars.
For 2026, the elective deferral cap is $24,500 if you are under 50. If you are 50 through 59 or 64 and older, you can add an $8,000 catch-up for a total of $32,500. If you are 60 through 63, a SECURE 2.0 enhanced catch-up of $11,250 replaces the standard one, bringing your ceiling to $35,750.1Internal Revenue Service. 401(k) Limit Increases to $24,500 for 2026, IRA Limit Increases to $7,500
What Your Paycheck Looks Like After the Cutoff
Your employer’s payroll system tracks year-to-date deferrals every pay cycle. Once cumulative contributions reach the applicable limit, deductions stop for the remainder of the year. Federal law requires the plan to enforce that ceiling, so at most employers this happens without any action from you.2Office of the Law Revision Counsel. 26 USC 401 – Qualified Pension, Profit-Sharing, and Stock Bonus Plans
The dollars that would have gone into your 401(k) stay in your gross pay and get taxed as ordinary income. Your net paycheck grows noticeably. Check the pay stub after the cutoff to confirm the year-to-date deferral total matches the IRS limit exactly. Payroll errors do happen, and fixing them before December 31 is far easier than filing a corrective distribution later.
The Match You Might Be Leaving Behind
Employer matching contributions are almost always calculated per pay period, not annually. A common formula matches 100% of the first 4% of pay each paycheck. If you contribute nothing in a given paycheck because you already hit the cap, the match for that period is zero too.
Say you earn $180,000 and your plan matches dollar-for-dollar on the first 4% of pay. Spreading a $24,500 deferral evenly across 24 pay periods works out to about $1,021 per period, with the employer adding roughly $300. Now suppose you front-load by deferring 30% of your pay. You hit $24,500 around mid-year, your deferral drops to zero for the remaining paychecks, and the match disappears with it. The forfeited employer contributions can run into the thousands.
True-Ups
Some plans fix this at year-end through a “true-up.” After December 31, the administrator compares your actual match against what it would have been with even contributions throughout the year and deposits the difference. The IRS has flagged the mismatch between annual match formulas and per-period calculations as a common compliance error, noting that “if your plan administrator calculates the matching contribution on a payroll period basis, rather than on an annual basis, at the end of the year, the sum of these amounts may not comply with the terms of the plan.”3Internal Revenue Service. 401(k) Plan Fix-It Guide – Employer Matching Contributions Weren’t Made to All Appropriate Employees
Not every plan offers one. Your Summary Plan Description will spell out how matching is calculated and whether year-end reconciliation exists. If it doesn’t, and you want the full match, spread your deferrals evenly so you are still contributing something in every pay period. Most payroll systems accept a flat dollar amount or percentage that gets you there.
Where to Put the Next Dollar
Maxing out your 401(k) does not exhaust the tax-advantaged options. Several other accounts have their own separate limits.
Traditional and Roth IRAs
For 2026, you can contribute up to $7,500 to a traditional IRA, a Roth IRA, or a combination. If you are 50 or older, an $1,100 catch-up raises the total to $8,600.1Internal Revenue Service. 401(k) Limit Increases to $24,500 for 2026, IRA Limit Increases to $7,500
Income limits apply. Roth IRA contribution eligibility phases out between $153,000 and $168,000 of modified adjusted gross income for single filers, and between $242,000 and $252,000 for married joint filers. Above those ranges, direct Roth contributions are off the table, though a backdoor Roth conversion may still work. For deductible traditional IRA contributions, the phaseout for single filers covered by a workplace plan runs from $81,000 to $91,000, and for joint filers where the contributing spouse has a workplace plan, $129,000 to $149,000.1Internal Revenue Service. 401(k) Limit Increases to $24,500 for 2026, IRA Limit Increases to $7,500
Health Savings Accounts
If you are enrolled in a high-deductible health plan, an HSA is one of the most efficient savings vehicles available. For 2026, the contribution limit is $4,400 for self-only coverage and $8,750 for family coverage.4Internal Revenue Service. Expanded Availability of Health Savings Accounts Under the OBBBA Notice 2026-05
HSAs deliver a triple tax benefit: contributions reduce taxable income, growth is tax-free, and withdrawals for qualified medical expenses are never taxed. After age 65, funds can be withdrawn for any purpose without penalty, though non-medical withdrawals are taxed as ordinary income much like a traditional IRA. For someone who has already maxed out a 401(k) and IRA, funding an HSA is usually the next best move.
After-Tax 401(k) Contributions and the Mega Backdoor Roth
Your $24,500 deferral limit is only part of the picture. A separate combined cap governs all money going into your account from every source, including your deferrals, employer match, profit-sharing, and any after-tax contributions. For 2026, that combined limit is $72,000, not counting catch-up contributions.5IRS. 2026 Amounts Relating to Retirement Plans and IRAs Notice 2025-67 For someone 50 or older the effective ceiling is $80,000; for ages 60 through 63, it’s $83,250.
Some plans allow after-tax contributions beyond the $24,500 deferral limit, up to that combined cap. Those contributions do not give you an upfront deduction, but earnings grow tax-deferred, and many plans let you roll the after-tax amounts into a Roth IRA either while still employed or after you leave.6Internal Revenue Service. Rollovers of After-Tax Contributions in Retirement Plans That maneuver is often called a mega backdoor Roth, and for a high earner who has already maxed regular deferrals it is the single most powerful shelter available. Not every plan permits after-tax contributions or in-service distributions, so check your plan document before counting on it.
Watch-Outs That Can Cost You
Changing Jobs Mid-Year
The $24,500 limit applies per person, not per plan. When you switch employers, the new payroll system starts from zero and will let you defer another full $24,500 based on wages earned there. Contribute $15,000 at Job A and $15,000 at Job B and you have exceeded the limit by $5,500.
You are responsible for tracking this. The simplest check is to compare Box 12, Code D on each W-2 you receive for the year, which reports 401(k) elective deferrals directly.7Internal Revenue Service. Common Errors on Form W-2 Codes for Retirement Plans If you know you will exceed the limit before year-end, tell the new employer’s payroll department to cap your deferrals at whatever room remains.
Fixing an Excess Deferral
If your total deferrals across all plans exceed the annual limit, request a corrective distribution from one of your plan administrators by April 15 of the following year. For excess deferrals made in 2026, the deadline is April 15, 2027. Filing a tax extension does not push it back.8Internal Revenue Service. Consequences to a Participant Who Makes Excess Deferrals to a 401(k) Plan
A timely correction distributes the excess plus attributable earnings. The excess is taxable in the year it was originally deferred; the earnings are taxable in the year distributed. There is no 10% early withdrawal penalty and no mandatory 20% withholding. Miss the deadline and the excess gets taxed twice: once in the year of deferral and again when eventually distributed, plus the 10% early distribution penalty if you are under 59½.8Internal Revenue Service. Consequences to a Participant Who Makes Excess Deferrals to a 401(k) Plan
If You Are a Higher Earner
Two rules kick in above certain wage thresholds. Traditional 401(k) plans must run annual nondiscrimination tests, and if the plan fails, some highly compensated employees can receive taxable refunds of their contributions even when they stayed within the $24,500 limit. For 2026, you are an HCE if you earned more than $160,000 from the employer in the prior year.5IRS. 2026 Amounts Relating to Retirement Plans and IRAs Notice 2025-67 Safe Harbor plans are exempt from this testing, so if yours is one, ADP refunds are not a concern.9Internal Revenue Service. 401(k) Plan Fix-It Guide – The Plan Failed the 401(k) ADP and ACP Nondiscrimination Tests
Separately, SECURE 2.0 requires that catch-up contributions be made as Roth (after-tax) rather than pre-tax if your wages from the plan-sponsoring employer exceeded $150,000 in the prior year. Final IRS regulations generally apply the requirement to taxable years beginning after December 31, 2026, though plans may implement earlier under a good-faith reading of the statute.10Internal Revenue Service. Treasury, IRS Issue Final Regulations on New Roth Catch-Up Rule, Other SECURE 2.0 Act Provisions Whether your 2026 catch-up must be Roth depends on your plan’s timing; ask the administrator. If you earn below $150,000, the rule does not touch you.