How a 401(k) Affects Your Paycheck: Before and After (2026)

Traditional 401(k) contributions reduce taxable wages while also moving part of each paycheck into retirement savings. These Texas examples use a $90,000 salary.

401(k) contribution	Annual contribution	Annual take-home	Biweekly take-home
0%	$0	$72,145	$2,774.81
3%	$2,700	$70,039	$2,693.81
6%	$5,400	$67,933	$2,612.81
10%	$9,000	$65,125	$2,504.81

How pre-tax 401(k) contributions change withholding

A traditional 401(k) contribution is usually deducted from gross pay before federal income tax and, in most states, before state income tax is calculated. Social Security and Medicare (FICA) still apply to the gross wages before the 401(k) deduction unless your plan has a specific exception — most W-2 employees pay FICA on full gross.

Because federal withholding tables use taxable wages, each percentage point of 401(k) contribution typically lowers federal withholding and increases net pay on each paycheck — but you also have less cash in your bank account because part of gross went to retirement. The net paycheck change is smaller than the contribution amount because tax withholding drops.

Example workflow for modeling 401(k) impact

Open any state paycheck calculator and enter your salary, filing status, and pay frequency. Add your planned annual 401(k) dollar amount or percentage in the pre-tax deductions field. Compare net pay with and without the contribution to see the tax savings side by side.

For salary benchmarks, start from $75k or $100k salary guides and layer in your 401(k) election. Roth 401(k) contributions are different — they do not reduce current taxable wages, so withholding does not drop the same way.

Annual limits and employer match

IRS sets annual employee contribution limits for 401(k) plans. Employer matching does not count toward your employee limit but is subject to separate overall plan limits. Your pay stub may show match as a separate line that does not reduce your take-home pay — it is an employer contribution to your retirement account.

State tax treatment

Most states that tax wage income follow federal treatment for traditional 401(k) deferrals. States with no income tax on wages — such as Texas and Florida — still benefit from lower federal withholding when you contribute pre-tax. High-tax states like California and New York can show a larger combined federal and state withholding reduction.

FAQ: 401(k) and take-home pay

Does a 401(k) always increase take-home pay? No. You divert part of gross to retirement. Withholding drops, so the paycheck decrease is smaller than the contribution, but net cash pay still usually falls unless tax savings fully offset the deferral (uncommon at moderate contribution rates).

Should I reduce withholding when I start a 401(k)? Your W-4 does not need a separate step for 401(k) — payroll systems reduce taxable wages automatically. If you still owe or receive large refunds, revisit your W-4 after major life or deduction changes.

Roth 401(k) vs traditional on your stub

Roth 401(k) contributions are post-tax — they do not reduce current federal or state withholding because taxable wages stay the same. Your paycheck drops by the full Roth contribution amount plus any change in other lines. Roth is valuable for tax diversification in retirement, but it does not increase current take-home pay the way traditional deferrals can.

Catch-up contributions for age 50+

Workers 50 and older may make additional catch-up contributions beyond the standard employee limit. Larger deferrals increase the withholding reduction from traditional contributions but also divert more cash from each paycheck to retirement. Model catch-up amounts explicitly in the calculator when planning year-end deferrals.

Employer match timing

Some employers match per paycheck; others match annually or quarterly. Match dollars usually do not appear as a deduction on your stub — they are employer contributions. Your personal cash flow changes only from your employee deferral, not from match timing.

Using ExactTakeHome for your situation

Every example in this guide uses engine-computed withholding from official 2026 tax tables — IRS Publication 15-T for federal income tax and state employer withholding schedules where state income tax applies. Open the paycheck calculator, select your state, enter your annual salary or hourly equivalent, and adjust filing status, pay frequency, and pre-tax deductions to match your pay stub inputs.

Salary band pages at /salary/ provide quick benchmarks at common amounts. Hourly routes at /hourly/ convert hourly rates to annual gross using 2,080 full-time hours. City guides at /city-salary/ add local wage tax when your work city levies one. Compare pairs at /compare/ when evaluating two states side by side.

Figures here are estimates for planning — not tax advice. Payroll rounding, mid-year law changes, and employer-specific benefit elections can shift your actual stub by small amounts. Consult a qualified tax professional for filing decisions and complex multi-state situations.

Frequently Asked Questions

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.