What if? · 401(k)
What maxing your 401(k) actually costs you.
Pre-tax 401(k) contributions cut your taxable income — so every dollar you save costs you less than a dollar of take-home. Drag the slider to see the real cash impact of any contribution level.
Your inputs
Edit anything — the result updates live.Because of the tax savings, every $1 you put in your 401(k) only reduces your take-home pay by about $0.78. The other $0.22 is money the IRS would have taken from you anyway.
2026 IRS elective deferral limit: $24,500. Catch-up contributions (50+, 60–63) not modeled.
How your contribution breaks down
The $24,500 that lands in your 401(k) every year. Less than all of it actually comes out of your pocket.
Tax year 2026 · Assumes W-2 wages, standard deduction
Your tax savings as contributions increase
From $0 up to the 2026 IRS max of $24,500. The dot is where the slider currently sits.
Worth knowing
401(k) contributions lower your federal income tax, but Social Security and Medicare taxes still apply to your full salary either way.
We don’t model state taxes (which often stack on top of the federal savings), Roth 401(k) contributions, or employer match. This shows the federal income-tax benefit of pre-tax contributions only.
Estimates only, for educational purposes. Federal taxes only. The calculator does not model state or local income tax, the Alternative Minimum Tax (AMT), the Net Investment Income Tax (NIIT), itemized deductions beyond the standard deduction, the QBI deduction, catch-up retirement contributions, HSA/FSA contributions, employer 401(k) match, self-employment tax, Roth conversions, multiple jobs, or phase-outs of credits and deductions. Not tax, legal, or financial advice. Consult a qualified tax professional before making any decision based on these numbers. Full terms →