Why your paycheck calculator and your real paycheck disagree
Three common reasons: (1) your W-4 withholding is conservative — employers withhold based on IRS tables, not the smooth math above, so paychecks early in the year often look smaller than this calculator suggests; (2) bonuses and RSUs are withheld at a flat 22% federal rate up to $1M (37% above), not your marginal bracket; (3) state and local rules vary — NYC, San Francisco, Philly, and several Ohio cities add local income tax this calculator doesn't model.
- • Update your W-4 if refunds or bills are consistently > $500 — you're financing the wrong direction.
- • Bonus checks are not 'over-taxed' — they're withheld at a flat rate, and you settle up at tax time.
- • If you have multiple jobs, use the IRS multi-job worksheet or Step 2(c) on the W-4 or you'll under-withhold.
The 401(k) trap most people fall into
Contributing the full match (often 3–6%) is non-negotiable — it's free money. Beyond that, the question is marginal tax rate today vs. in retirement. If you're in the 12% federal bracket, Roth 401(k) usually wins. If you're in the 24%+ bracket and expect a lower retirement bracket, traditional pre-tax wins. The 22% bracket is the toss-up zone where Roth and traditional are close to a wash.
State strategy: where the no-tax states actually pay off
Texas, Florida, Tennessee, Washington, Nevada, South Dakota, Wyoming, Alaska, and New Hampshire (NH taxes only interest/dividends) have no state income tax. But they offset with higher property tax (TX, NH), sales tax (WA, TN), or insurance costs (FL, NV). The break-even vs. a 5–9% state-tax state usually lands around $90–120k income; below that, the savings rarely cover the offsets.
What this calculator does NOT include
Local/city income tax (NYC, SF, Philly, Detroit, several Ohio + KY cities), pre-tax dependent care FSA, after-tax Roth 401(k), HSA family limits ($8,550 in 2025 vs $4,300 single), Social Security tax on second jobs (you can recover it on your return), and the QBI deduction for 1099 / S-corp income. Use the IRS Tax Withholding Estimator for an audit-grade number.
FAQ
Is this calculator accurate for 2025?
It uses the 2025 federal brackets, $14,600 single standard deduction, $168,600 SS wage base, $23,500 401(k) limit, and 1.45% Medicare + 0.9% additional Medicare over $200k. State tax is modeled as a flat top rate — fine for FL/TX/no-tax states and roughly accurate for most flat-tax states, less precise for highly graduated states like CA where your effective rate is lower than the top marginal.
Why does the calculator default to single filer status?
Single brackets and the $14,600 standard deduction are the worst-case (highest tax) for any given income — anyone married filing jointly or head of household will take home more than this number, so we err on the conservative side. Multiply your gross by ~1.04–1.08 to approximate MFJ take-home.
How do I figure out my real state tax rate?
Pull last year's state return and divide state tax owed by gross income. That's your effective state rate. For CA, NY, NJ, HI use the top bracket if you're over $100k; for flat-tax states (CO 4.4%, IL 4.95%, MA 5%, MI 4.25%, NC 4.5%, PA 3.07%, UT 4.55%) use the headline rate.
What's the difference between gross, taxable, and net?
Gross is your stated salary. Taxable is gross minus pre-tax benefits (401k, health, HSA) and the standard or itemized deduction. Net (take-home) is gross minus all taxes minus all pre-tax deductions. The number you actually see in your account is net.
Why is my first paycheck of the year smaller?
SS tax (6.2%) is withheld until you hit $168,600 of cumulative wages. High earners cross that cap mid-year and get a noticeable paycheck bump for the rest of the year. Your 401(k) also stops once you hit $23,500.
Does pre-tax 401(k) reduce my state tax?
In 41 states, yes. Pennsylvania is the big exception — PA taxes 401(k) contributions when you make them but not when you withdraw. New Jersey partially follows the same logic. In every other state, pre-tax 401(k) reduces your state taxable income just like federal.
Should I max my 401(k) before contributing to a Roth IRA?
Capture full employer match → Roth IRA (if under income limits) → max 401(k) → HSA → backdoor Roth. The order optimizes for tax diversification rather than pure rate arbitrage.
How does a bonus get taxed?
Federal withholding on supplemental wages is a flat 22% (up to $1M; 37% above). State withholding varies. Your actual tax owed is your marginal rate, so a $10k bonus when you're in the 32% bracket will be under-withheld by ~10% and you'll owe the difference at tax time — or get the excess back if you're in a lower bracket.
What about RSUs and stock comp?
RSU vesting is treated as supplemental wages and withheld at the flat 22% / 37% rate. Almost everyone in tech under-withholds on RSUs and either owes at tax time or has their broker sell extra shares ('sell to cover'). Use the RSU vesting calculator for the full picture.
How accurate is this for self-employed / 1099 income?
Not accurate — 1099 income pays full 15.3% SE tax (not 7.65%), no employer withholding, quarterly estimated payments, and gets the 20% QBI deduction. Use the freelance / creator tax calculators for that scenario.
How this calculator is built
Independently maintained
Written by Sam Doshi and the RevenueLab editorial team. We don't sell the data feeds this tool is built on.
Sourced from primary data
Benchmarks come from public AdSense / Stripe / IRS disclosures and reader-submitted data — never third-party "$X per view" claims. Full methodology.
Last reviewed
June 2026. We re-check every figure on the platform on a rolling quarterly cycle.
Editorial standards
See our editorial policy and disclaimer. Results are estimates, not advice.