401(k) Contribution Calculator

401(k) Contribution Calculator: What It Shows

This calculator shows you three things at once: how your 401(k) contribution affects your actual take-home pay (less than you think, thanks to the tax break), how your balance grows to retirement, and a side-by-side comparison of Traditional vs Roth so you can make an informed choice.

Why Traditional 401(k) costs less than you expect

A traditional 401(k) contribution reduces your taxable income before federal and state income taxes are calculated. At a 22% marginal rate, a $300 contribution only reduces your take-home by about $234 — the other $66 is pure tax savings. The higher your bracket, the better the immediate deal. This is why financial advisors often say "contribute enough to get the match, then decide."

The employer match is a guaranteed 50–100% return

If your employer matches 50 cents per dollar up to 6% of salary, and you contribute 6%, you've just earned a guaranteed 50% return on that money before it's even invested. No other investment offers a risk-free 50–100% instant return. The #1 financial mistake many Americans make is not contributing enough to capture their full employer match.

The 2026 contribution limits

The 401(k) employee contribution limit for 2026 is $23,500 for those under 50. Workers aged 50–59 and 64+ can add a $7,500 catch-up contribution ($31,000 total). Workers aged 60–63 have an enhanced catch-up of $11,250 under SECURE 2.0 ($34,750 total). These limits apply to traditional and Roth contributions combined.

Traditional vs Roth — the key question

If you expect to be in a higher tax bracket in retirement than you are today, Roth wins — you pay taxes now at the lower rate and withdrawals are tax-free. If you're in your peak earning years and expect lower income in retirement, Traditional wins — you defer taxes to a lower-rate future. When uncertain, splitting contributions is a common and reasonable hedge.