401(k) Calculators
401(k) Paycheck Calculator
See your full paycheck breakdown with a 401(k) contribution factored in — gross pay, your contribution, FICA, federal and state tax, and what actually lands in your bank account.
Calculate your paycheck
FICA is calculated on your full gross wages — 401(k) contributions, Traditional or Roth, never reduce Social Security or Medicare tax. Only Traditional contributions reduce federal (and state) income tax.
How to calculate 401(k) from paycheck
Four deductions, applied to two different bases.
Your contribution
Gross pay × your contribution %, taken off the top before anything else.
FICA
6.2% Social Security (up to a wage cap) + 1.45%+ Medicare — on full gross pay, unaffected by your 401(k).
Federal & state tax
Applied to gross pay minus your Traditional contribution (Roth doesn't reduce this).
What's left
Gross pay, minus all four deductions above, is your net take-home pay.
How to calculate 401(k) from paycheck, step by step
A 401k paycheck calculator, 401k paycheck impact calculator, payroll calculator with 401k, paycheck 401k calculator, 401k calculator paycheck, or paycheck calculator 401k question is really asking for a full gross-to-net breakdown with a retirement contribution added in. To how to calculate 401k from paycheck by hand: start with gross pay for the period, subtract your contribution, subtract FICA (calculated on the original gross, not the reduced amount), subtract federal and state income tax (calculated on gross minus your Traditional contribution), and what's left is your net pay.
Why your 401(k) contribution doesn't lower FICA
This is the single most common misunderstanding a 401k salary calculator or 401k paycheck deduction calculator has to get right: 401(k) contributions — Traditional or Roth — reduce the income you're taxed on for federal (and usually state) income tax, but not for Social Security and Medicare. FICA taxes apply to your full gross wages regardless of how much you defer.
| Tax | Rate | Applies to |
|---|---|---|
| Social Security | 6.2% | Full gross wages, up to $184,500 (2026 cap) |
| Medicare | 1.45% | Full gross wages, no cap |
| Additional Medicare | 0.9% | Wages above $200,000 ($250,000 MFJ) |
| Federal income tax | 10–37% | Gross wages minus Traditional 401(k) contribution |
401(k) take-home pay impact: Traditional vs. Roth
A 401k take home calculator shows a real difference between the two contribution types. A Traditional contribution shrinks your paycheck by less than the raw dollar amount, since it also lowers the income tax withheld from that same check. A Roth contribution shrinks your paycheck by the full amount — no offsetting tax reduction — because you're contributing money that's already been taxed.
Roth 401(k) and your paycheck specifically
A roth 401k paycheck calculator or paycheck calculator with roth 401k search wants to see that full-amount impact directly. Switch the calculator above to "Roth" and compare the net pay figure against "Traditional" at the same contribution percentage — the gap between the two is exactly the tax savings you're giving up today in exchange for tax-free withdrawals later.
FICA rates and the 2026 Social Security wage base ($184,500) are verified against IRS Topic 751 and current payroll guidance. This is a paycheck estimate, not a substitute for your actual pay stub — your employer's payroll system is the authoritative source.
Frequently asked questions
Before you check your next pay stub.
Does a 401(k) contribution reduce my Social Security and Medicare tax?
No. FICA taxes (Social Security and Medicare) are calculated on your full gross wages regardless of how much you contribute to a 401(k), Traditional or Roth. Only federal and state income tax withholding are reduced, and only by Traditional contributions.
Why did my paycheck drop by more than my contribution percentage?
It shouldn't, for the contribution itself — but if you increased a Roth contribution specifically, remember there's no offsetting tax reduction the way there is with Traditional, so the full dollar amount comes straight off your take-home pay.
Is there a cap on how much Social Security tax I pay?
Yes — Social Security tax only applies to the first $184,500 of wages in 2026. Once your year-to-date wages cross that amount, Social Security withholding stops for the rest of the year (Medicare continues with no cap).
Does increasing my 401(k) contribution lower my tax bracket?
It can reduce your taxable income enough to lower your effective tax rate, and in some cases move you into a lower marginal bracket, but only for Traditional contributions — Roth contributions don't reduce taxable income at all.
What's the difference between this and the Max Contribution Calculator?
This tool shows your full paycheck breakdown at any contribution percentage you choose. The Max Contribution Calculator works backward from the IRS annual limit to tell you the exact percentage or dollar amount needed to hit it by year-end.