Are 401(k) Contributions Tax Deductible In 2026?

Last updated 05/13/2026 by

Ante Mazalin

Edited by

Andrew Latham

Fact checked by

Andy Lee

Summary:

Traditional 401(k) contributions reduce your taxable income, but for W-2 employees, this tax benefit happens automatically through payroll. Your employer excludes the contributions from the wages reported in Box 1 of your W-2, so there is no separate deduction to claim on Form 1040.

Roth 401(k) contributions use after-tax dollars with no current deduction. Self-employed individuals with a solo 401(k) do claim a deduction on Schedule 1.

Traditional 401(k), W-2 employees: Pre-tax contributions reduce taxable wages at the source. Your employer does not include 401(k) deferrals in the Box 1 wages on your W-2. No separate deduction entry on Form 1040 is needed. The contribution limit for 2025 is $23,500 ($31,000 for participants age 50 or older, or up to $34,750 for eligible participants ages 60–63 under SECURE 2.0).
Roth 401(k), W-2 employees: Contributions are made with after-tax dollars. No current tax deduction is available. Qualified distributions in retirement are tax-free.
Self-employed / solo 401(k): The employer contribution portion is deductible as a business expense on Schedule 1 (Form 1040), Line 16, per IRS Publication 560. The employee deferral portion reduces self-employment income. Combined, both portions must stay within the annual overall plan limit.
Employer matching contributions: Not deductible by the employee. Employer matches are excluded from the employee’s income and deducted by the employer on the business return, not on the employee’s individual return.

Whether a 401(k) contribution “counts” as a deduction depends on how you earn your income. For most people, the answer is that the tax benefit is real, but it never shows up as a line item on a Form 1040.

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Are 401(k) contributions tax-deductible? Yes, for traditional accounts, but the deduction works differently than most

Yes, traditional 401(k) contributions reduce your taxable income, but the mechanism depends on how you work. For W-2 employees, contributions are excluded from taxable wages at the payroll stage, before your W-2 is even generated, so no deduction needs to be claimed on your return.

According to IRS Publication 525, elective deferrals to a 401(k) plan are excluded from the employee’s income and not included in Box 1 (wages) of Form W-2. Box 12 of the W-2 shows the contribution amount with code D, but this is informational, the income exclusion already happened through payroll.

The employee does not claim a Schedule A or Schedule 1 deduction for the deferral.

For self-employed individuals who sponsor their own solo 401(k), the employer contribution portion must be claimed as a deduction on Schedule 1 (Form 1040), Line 16, calculated using IRS Publication 560.

Who benefits from the 401(k) tax advantage?

The tax benefit varies significantly depending on the account type and employment status.

W-2 employees with a traditional 401(k): Contributions are excluded from taxable wages by the employer. Per IRS Publication 525, these elective deferrals are not included in Box 1 of Form W-2, which directly reduces the income reported on Form 1040. The employee owes no federal income tax on the contributed amount until withdrawal. No action on Form 1040 is required to claim this benefit, it is already reflected in the W-2.
W-2 employees with a Roth 401(k): Contributions are included in taxable wages and appear in Box 1 of the W-2. There is no current-year tax deduction. Per the IRS Roth comparison chart, the trade-off is that qualified distributions from a Roth 401(k), including earnings, are tax-free in retirement. Box 12 of the W-2 shows Roth 401(k) contributions with code AA.
Self-employed individuals with a solo 401(k): Eligible for two types of contributions: an employee elective deferral (which reduces net self-employment income) and an employer profit-sharing contribution (which is deductible on Schedule 1, Line 16). Per IRS Publication 560, the total combined contribution, employee deferral plus employer contribution, cannot exceed the lesser of 100% of compensation or the applicable annual overall limit. The deductible employer contribution is calculated on a worksheet in Publication 560.
Employees who contributed over the annual limit: Excess deferrals beyond the annual limit are includible in gross income in the year contributed. Per IRS guidance on retirement topics, an employee who over-contributes must notify the plan administrator by April 15 of the following year to receive a corrective distribution. If the excess is not distributed, it may be taxed twice, once when contributed and again when distributed.

The tax benefit of a traditional 401(k) is real regardless of whether the filer itemizes.

Because the contribution reduces wages reported on the W-2, the income reduction flows to Form 1040 automatically and reduces the base for calculating federal income tax, the self-employment tax (for self-employed), and income-based thresholds like the IRMAA surcharge on Medicare premiums.

How much of 401(k) contributions are tax-advantaged?

The 2025 employee elective deferral limit and applicable catch-up amounts set the maximum pre-tax benefit for the year. The IRS adjusts these limits annually for cost-of-living increases.

Account type / filer	2025 contribution limit	Tax treatment
Traditional 401(k), W-2 employee (under age 50)	$23,500 employee deferral	Pre-tax; excluded from W-2 Box 1 wages; no Form 1040 entry needed
Traditional 401(k), W-2 employee (age 50+)	$31,000 ($23,500 + $7,500 catch-up)	Pre-tax; excluded from W-2 Box 1 wages; no Form 1040 entry needed
Traditional 401(k), W-2 employee (ages 60–63, SECURE 2.0)	Up to $34,750 ($23,500 + $11,250 super catch-up)	Pre-tax; excluded from W-2 Box 1 wages; no Form 1040 entry needed
Roth 401(k), W-2 employee	Same contribution limits as traditional (same plan limits apply)	After-tax; included in W-2 Box 1; no current deduction; tax-free qualified withdrawals
Solo 401(k), self-employed (employer contribution portion)	Up to 25% of net self-employment compensation; combined employee + employer cannot exceed $70,000 (2025)	Deductible on Schedule 1 (Form 1040), Line 16, per IRS Publication 560

The $70,000 overall 2025 plan limit for solo 401(k) contributions applies to the combined total of employee deferrals and employer profit-sharing contributions. Catch-up contributions for eligible participants are not counted against this combined cap, per IRS retirement plan guidelines.

How traditional 401(k) contributions work on your tax return

For most employees, no tax return action is required, the benefit is already in the W-2. Self-employed filers have an additional step. Here is the process for both groups.

For W-2 employees, verify Box 1 and Box 12 on your W-2 when it arrives in January. Box 1 shows your taxable wages after the 401(k) deferral has been excluded. Box 12 with code D shows the traditional 401(k) deferral amount for your records. Box 12 with code AA shows Roth 401(k) contributions. Per IRS Publication 525, there is no entry to make on Form 1040 to claim the tax benefit for a traditional 401(k) deferral, it is already reflected in the lower Box 1 amount.
Confirm you did not exceed the annual deferral limit. Per IRS retirement plan guidelines, the 2025 employee elective deferral limit is $23,500, or $31,000 if you are age 50 or older. Participants ages 60 through 63 may contribute up to $34,750 under the SECURE 2.0 Act super catch-up provision. If you participated in multiple employer plans during the year, the deferral limit applies to your combined contributions across all plans.
For self-employed filers with a solo 401(k), calculate the deductible employer contribution using IRS Publication 560. The employer contribution is limited to 25% of net self-employment compensation (after deducting the contribution itself and the self-employment tax deduction). Publication 560 includes a rate table and worksheet to calculate the correct employer contribution percentage from your net self-employment earnings.
Self-employed filers: enter the deductible employer contribution on Schedule 1 (Form 1040), Part II, Line 16. This above-the-line deduction reduces your adjusted gross income and is available whether or not you itemize. The employee deferral portion of a solo 401(k) reduces self-employment income at the source and does not appear separately on Schedule 1.
Keep W-2s, plan contribution statements, and solo 401(k) calculation worksheets for at least three years. Per IRC Section 6501, the IRS can audit returns within three years of the filing date. For self-employed filers who deduct a solo 401(k) employer contribution on Schedule 1, retain the Publication 560 worksheet and the plan’s contribution records to document that the deduction was correctly calculated.

Common mistakes with 401(k) tax treatment

The most common error for W-2 employees is looking for a 401(k) deduction line on Form 1040 and assuming the contribution was not tax-advantaged when no entry appears. Traditional 401(k) deferrals are excluded from Box 1 of the W-2 before the return is filed, the tax reduction already happened.

There is no corresponding line on Schedule 1 for an employee’s 401(k) deferral, and the absence of one does not mean the benefit was lost.

A related mistake is confusing a traditional 401(k) with a traditional IRA in terms of how the deduction is reported. An IRA deduction for eligible filers is claimed on Schedule 1 (Form 1040), Line 20, and must be entered manually. The 401(k) deferral works differently and requires no Form 1040 entry for W-2 employees. Entering 401(k) contributions again on Schedule 1 after they have already been excluded from W-2 wages results in a double deduction.

Exceeding the annual deferral limit across multiple plans: Per IRS retirement plan guidelines, the $23,500 elective deferral limit applies across all 401(k) plans and 403(b) plans in which a participant is enrolled during the year. An employee who works for two unrelated employers and contributes the maximum to each plan has exceeded the limit. Excess deferrals above the annual limit are includible in gross income and may be taxed twice if not timely corrected.
Self-employed filers deducting the employee deferral portion on Schedule 1: For solo 401(k) plans, only the employer contribution portion is deducted on Schedule 1, Line 16. The employee elective deferral reduces net Schedule C self-employment income at the source and should not also be reported on Schedule 1 as a separate deduction. Deducting both components on Schedule 1 overstates the deduction.
Omitting Roth 401(k) contributions from W-2 review: Some employees assume that because Roth 401(k) contributions appear on their pay stubs, they will be reflected somewhere on their tax return as a deduction. They will not. Roth contributions are made with after-tax dollars that are already included in Box 1 wages on the W-2. No current deduction is available, and no Form 1040 entry is needed. The long-term benefit is tax-free withdrawal, not a current deduction.

Pro tip: Self-employed filers who establish a solo 401(k) must adopt the plan document by December 31 of the tax year for which they want to make contributions, but they can make the actual employer contribution as late as the tax return due date including extensions (typically October 15 for individuals who file for an extension). This means a self-employed filer who had an unexpectedly profitable year has until the extended return due date to make a solo 401(k) employer contribution, calculate the deduction in Publication 560, and reduce their Schedule C net earnings retroactively. This timing flexibility makes the solo 401(k) one of the most effective last-minute tax-reduction tools for the self-employed, but the plan must have been established before year-end for the contribution to count.

Unlike an IRA contribution, which can also be made after year-end up to the filing deadline, the 401(k) employee deferral for W-2 employees must be made during the calendar year. There is no opportunity to make additional employee deferrals after December 31 for the prior year, even if the return is filed on extension.

Key takeaways

Traditional 401(k) contributions reduce taxable income for W-2 employees, but the tax benefit happens through the payroll system, the contributions are excluded from Box 1 of the W-2. No deduction entry is needed on Form 1040. The 2025 employee deferral limit is $23,500 ($31,000 for age 50+, up to $34,750 for ages 60–63 under SECURE 2.0).
Roth 401(k) contributions are made with after-tax dollars included in Box 1 of the W-2. There is no current deduction. The tax benefit is tax-free qualified withdrawals in retirement, per the IRS Roth comparison chart.
Self-employed individuals with a solo 401(k) can deduct the employer profit-sharing contribution portion on Schedule 1 (Form 1040), Line 16, per IRS Publication 560. The total combined employee deferral plus employer contribution cannot exceed $70,000 for 2025.
The $23,500 deferral limit applies to combined contributions across all 401(k) and 403(b) plans in which a participant is enrolled in the same year. Exceeding the limit results in an excess deferral that is includible in gross income and must be corrected by April 15 of the following year.

Frequently asked questions about 401(k) tax deductions

Can you deduct 401(k) contributions without itemizing?

Yes. For W-2 employees with a traditional 401(k), no deduction entry is needed at all, the tax benefit is already embedded in the Box 1 wages on your W-2 before the return is filed. For self-employed filers who deduct a solo 401(k) employer contribution on Schedule 1, the deduction is above the line and does not require itemizing on Schedule A.

Both types of tax benefit are available to standard deduction takers and itemizers alike.

Are 401(k) contributions deductible for rental property owners?

Not through their rental activity. Rental property owners who also have W-2 income can make traditional 401(k) contributions through their W-2 employer and receive the same payroll-level tax exclusion as any other employee.

Rental income on Schedule E is not earned income that can support 401(k) contributions directly. Self-employed owners who have Schedule C income in addition to rental income can make solo 401(k) contributions based on their net self-employment earnings, not on rental income.

What records do you need for 401(k) tax purposes?

Retain your annual W-2 showing Box 1 wages and Box 12 codes D or AA (for traditional or Roth 401(k) contributions), your year-end 401(k) plan statement showing total contributions made during the year, and your plan contribution confirmation for any catch-up contributions.

Self-employed filers should also keep their Publication 560 worksheets and the solo 401(k) plan document. Per IRC Section 6501, retain all records for at least three years from the filing date.

Does contributing to a 401(k) affect IRA contribution eligibility?

Participating in a 401(k) plan can reduce or eliminate the deductibility of a traditional IRA contribution, depending on income. Per IRS Publication 590-A, if you or your spouse is covered by a workplace retirement plan, the deductible IRA contribution phases out at modified AGI thresholds.

For 2025, the phase-out begins at $79,000 for single filers and $126,000 for married filing jointly when the contributing spouse is covered by a workplace plan. Contributing to a 401(k) does not affect eligibility to make Roth IRA contributions, which have separate income limits.

If you are self-employed and want to determine the maximum deductible contribution to a solo 401(k) based on your net earnings, or if you want to confirm whether your 401(k) participation affects the deductibility of a traditional IRA contribution, a tax professional can run both calculations for your specific income. SuperMoney’s tax preparation services comparison includes CPAs and enrolled agents with experience in retirement plan deductions. Filers who are also evaluating traditional IRA deductibility alongside their 401(k) can review how Roth IRA contributions work to compare the current versus future tax treatment of each option.

Disclaimer:The information on this page is for general educational purposes only and does not constitute tax, legal, or financial advice. Tax laws are subject to change and vary based on individual circumstances. The content reflects IRS rules as of the date this article was last updated and may not account for recent legislative or regulatory changes. SuperMoney is not a licensed tax advisor, and nothing on this page creates an advisor-client relationship. Consult a licensed CPA or tax professional for guidance specific to your situation.

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