401(k) vs Roth 401(k): The Real Paycheck Impact
Traditional and Roth 401(k) contributions look similar on paper but affect your take-home pay very differently. Here's the math for 2026.
The one-sentence difference
Traditional 401(k) contributions are pre-tax: you skip income tax now and pay it in retirement. Roth 401(k) contributions are post-tax: you pay income tax now and withdraw tax-free in retirement.
How each affects your paycheck
Say you earn $6,000 gross semi-monthly and contribute 10% ($600). With a traditional 401(k), federal income tax is calculated on $5,400. With Roth, it's calculated on the full $6,000 — you'll take home less today.
Both plans keep FICA on the full $6,000. Social Security and Medicare do not care whether your contribution is pre- or post-tax.
State tax treatment
Most states mirror federal treatment — a traditional 401(k) reduces state wages too. Pennsylvania is the notable exception: traditional 401(k) contributions are fully taxable at the state level.
If you're a high earner in a high-tax state (California, New York), the current tax savings of a traditional 401(k) can be significant.
2026 contribution limits
The IRS-announced 2026 elective deferral limit is $24,000. Workers age 50+ can contribute an additional $8,000 catch-up. The combined employee + employer limit is $71,000 (or $79,000 with catch-up).
Which should you pick?
Rule of thumb: choose traditional if you expect to be in a lower tax bracket in retirement. Choose Roth if you expect to be in the same or higher bracket. Young workers with rising incomes often lean Roth; peak earners often lean traditional.
Many plans let you split contributions between both. This is a legitimate hedging strategy — see our calculator to model each side against your salary.