Paycheck Guide · 401(k) · 2026
How 401(k) Contributions Reduce Your Taxes
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A traditional 401(k) contribution can lower current federal income-tax withholding because the deferral generally reduces wages subject to federal withholding. It does not work the same way as a Roth 401(k), and it does not eliminate Social Security or Medicare withholding.
Traditional vs. Roth 401(k)
A traditional contribution usually reduces current federal taxable wages. A Roth contribution does not provide that upfront withholding reduction, but qualified withdrawals may receive different treatment in retirement. Your plan documents and long-term goals matter.
Engine-Derived Example: $100,000 Salary With a 6% Contribution
For a single filer in Texas earning $100,000, a 6% traditional 401(k) election contributes $6,000 during the year. The calculator derives federal withholding of $13,170 without the contribution and $11,850 with it, a difference of $1,320.
| Scenario | Federal withholding | Annual take-home |
|---|---|---|
| No traditional 401(k) contribution | $13,170 | $79,180 |
| Traditional 401(k): 6% | $11,850 | $74,500 |
The contribution still reduces cash take-home because money moves into the retirement account. The federal withholding reduction softens that paycheck impact. FICA remains based on gross wages for this example.
Contribution Limits and Employer Match
Contribution limits and catch-up rules change over time. Review the IRS announcement for current limits. If your employer offers a match, review the plan rules so you understand how much you need to contribute to receive the available match.
Model your own traditional 401(k) election in the calculator.
See your take-home with 401(k) →Frequently Asked Questions
Does 401(k) reduce federal income tax?
Traditional 401(k) contributions generally reduce wages subject to current federal income-tax withholding. State treatment depends on the state's rules.
What is the 401(k) contribution limit for 2026?
Contribution limits can change by tax year and situation. Check the linked IRS announcement for the current limits and catch-up rules.
Does 401(k) reduce FICA taxes?
No. Traditional 401(k) elective deferrals generally do not reduce Social Security or Medicare wages.
Figures and methods are based on official-source data encoded in the calculator. Not tax advice. Review the methodology and consult a qualified professional for your situation.