The Short Version

A 401(k) contribution doesn't hit your paycheck as hard as the raw numbers suggest. That's because pre-tax contributions reduce your taxable income—so the government effectively subsidizes part of every dollar you save. For most people in the 22% federal bracket, contributing $300 per biweekly paycheck only reduces take-home by about $234.

Pre-Tax vs. Roth 401(k): The Key Difference

Traditional pre-tax 401(k) contributions come out of your gross pay before taxes are calculated. This lowers your taxable income for the year, reducing both federal and state taxes. You pay income tax on withdrawals in retirement.

Roth 401(k) contributions are made with after-tax dollars—you pay income tax upfront, but withdrawals in retirement are completely tax-free. This is the smarter play if you expect your tax rate to be higher later in life.

2026 Contribution Limits

The IRS raised 401(k) limits for 2026: $24,500 for employees under 50, and $32,500 for those 50 and older (including the $8,000 catch-up provision). These apply to the combined total of pre-tax and Roth contributions across all your employer plans. The employer match doesn't count toward these limits.

Real Tax Savings Example

Let's say you're single, earning $75,000 in 2026, and contribute $6,000 (8%) to a traditional pre-tax 401(k). Here's what happens:

Your taxable income drops from $75,000 to $69,000. In the 22% federal bracket, that saves you $1,320 in federal taxes annually. FICA savings: $372 (since the first $184,500 is subject to payroll tax). State savings vary—about $300 in California or $180 in New York. Total tax saved: roughly $1,992–$2,064.

But here's the powerful part: you contributed $6,000 out of pocket, but your take-home only dropped by approximately $4,008–$4,068. The government picked up nearly $2,000 of the tab through tax deferral.

Calculator Demo

See exactly how 401(k) contributions change your taxable income and real out-of-pocket cost. Adjust the percentage to model different savings rates.

The Long-Term Tradeoff

Pre-tax 401(k) offers immediate tax relief, which is great if you need the cash flow now or are in a high bracket. But when you withdraw the money in retirement, you'll pay ordinary income tax—potentially at a similar or higher rate. This is a bet that your future tax rate will be lower than your current one.

Roth 401(k) gives up the immediate tax break in exchange for tax-free withdrawals forever. This is ideal if you're early in your career (lower tax bracket now) or expect tax rates to rise in the future. The 2026 SECURE 2.0 provisions make Roth even more attractive by allowing employer match contributions to be treated as Roth in some plans.

The Employer Match: Don't Leave Free Money on the Table

If your employer offers a 401(k) match—say, 50% of the first 6% you contribute—you should contribute at least enough to get the full match. This is an instant 50% return on your money with zero risk. For someone making $75,000, that's $2,250 in free employer contributions annually on top of your $4,500 personal contribution to hit the 6% threshold.

One More Consideration

If you're already maxing out your emergency fund and have extra cash flow, contributing more to your 401(k) is almost always a better move than keeping money in a taxable brokerage account first. The tax-deferred growth and employer match make 401(k) the most efficient savings vehicle available to most workers.