401(k) Contribution Impact Calculator
See exactly how much take-home pay changes at different 401(k) contribution levels — and why it's less than the contribution itself. Calculations run in your browser.
This uses simplified defaults (no W-4 Step 2-4 adjustments, no other deductions) to isolate exactly what changing your 401(k) contribution does to take-home pay. Use the full paycheck calculator for your exact situation.
Take-home pay by 401(k) contribution
| Contribution | Per paycheck | Take-home | Take-home drops by |
|---|---|---|---|
| 0% | $0 | $2,369 | — |
| 3% | $87 | $2,301 | $68 |
| 6% | $173 | $2,234 | $135 |
| 10% | $288 | $2,144 | $225 |
| 15% | $433 | $2,021 | $348 |
| 20% | $577 | $1,894 | $475 |
"Take-home drops by" is less than the contribution itself — the difference is the federal (and where applicable, state) income tax you don't pay on money that goes into a traditional 401(k).
401(k) calculator FAQs
Why doesn't my take-home pay drop by the full contribution amount?
A traditional 401(k) contribution reduces the wages your federal (and most states') income tax is calculated on, before it's withheld. So increasing your contribution lowers your income tax at the same time it lowers your paycheck — the net drop in take-home pay is smaller than the contribution itself.
Does a 401(k) contribution reduce Social Security and Medicare tax too?
No. Traditional 401(k) contributions are exempt from federal (and most state) income tax, but they're still subject to Social Security and Medicare (FICA) tax — those are calculated on your full gross wages regardless of 401(k) contributions.
What about a Roth 401(k)?
Roth 401(k) contributions are made with after-tax dollars — they don't reduce your taxable wages at all, so your take-home pay drops by the full contribution amount. This calculator models a traditional (pre-tax) 401(k).