Paycheck Calculator
See the real take-home cost of contributing to a 401(k), 403(b), or 457. A pre-tax contribution lowers your paycheck by less than you put in — because it also lowers your income tax. Compare pre-tax vs. Roth and watch what it grows to by retirement.
Contributing $225 per paycheck reduces your take-home by only
$198
Each $1.00 you save costs just $0.88 of take-home — $27/paycheck in tax savings
Net Take-Home
$2,997/pay
Tax Savings
$27/pay
Balance at 65
$297,963
Monthly Income (4% SWR)
$993/mo
Your Paycheck, Line by Line
2026 federal brackets · FICA on gross wages
Model this with a client
RetirementForge runs paycheck, Roth, income-gap, and Social Security scenarios in a live, compliant client session.
For educational purposes only; not tax or financial advice. Estimates use 2026 federal tax brackets and FICA rates and assume the standard deduction, no state or local income tax, and no other withholdings. Pre-tax deferrals reduce income tax but not FICA. Projections assume level contributions and a 6% annual return and do not reflect IRS contribution limits or taxes at withdrawal. Confirm current figures and consult a qualified advisor.
Frequently Asked Questions
- How much does a 401(k) contribution actually reduce my paycheck?
- A pre-tax 401(k), 403(b), or 457 contribution reduces your take-home pay by less than the amount you contribute, because the contribution also lowers your taxable income. If you are in the 22% federal bracket, contributing $100 reduces your take-home by roughly $78 — the other $22 is income tax you would have paid anyway. The exact figure depends on your bracket and any state income tax. FICA (Social Security and Medicare) is still owed on the full amount, so pre-tax deferrals do not reduce payroll tax.
- Why does contributing $500 only cost me $390 in take-home?
- Because a pre-tax contribution is deducted before income tax is calculated. The money that would have gone to the IRS as income tax instead stays in your retirement account. That gap — between the contribution and the actual drop in your paycheck — is the tax savings. It is larger the higher your marginal tax bracket, which is why higher earners see the biggest paycheck efficiency from pre-tax deferrals.
- What is the difference between a pre-tax and a Roth contribution on my paycheck?
- A pre-tax contribution lowers your taxable income now, so your take-home drops by less than the contribution and you pay tax later when you withdraw in retirement. A Roth contribution is made with after-tax dollars, so it reduces your take-home dollar-for-dollar today, but qualified withdrawals in retirement are tax-free. This calculator lets you toggle between the two to compare the immediate paycheck impact.
- Does a pre-tax 401(k) contribution reduce Social Security and Medicare taxes?
- No. FICA taxes — 6.2% for Social Security up to the annual wage base and 1.45% for Medicare — are calculated on your gross wages before retirement deferrals. Only federal and state income taxes are reduced by a pre-tax 401(k), 403(b), 457, or TSP contribution. This calculator reflects that by applying FICA to gross pay regardless of your contribution.
- How much should I contribute to my 401(k)?
- A common starting point is to contribute at least enough to capture your full employer match, since that is an immediate return on your money. Beyond that, the right amount depends on your retirement income goal, years to retirement, and current budget. Use this calculator to see how a given contribution rate affects both your paycheck today and your projected balance and monthly income at retirement, then adjust until the trade-off feels right.
- Are these paycheck figures exact?
- They are a close estimate for planning discussions, not a payroll-exact figure. The calculator uses 2026 federal tax brackets and the standard deduction, plus FICA, but does not model state or local income taxes, other payroll withholdings, IRS contribution limits, or your specific W-4 elections. Your actual paycheck may differ. Confirm details with a tax professional.