About & methodology

How PaycheckSmart gets the numbers right

PaycheckSmart shows your real take-home pay — after federal tax, FICA, and your state's withholding — without a sign-up or a spreadsheet. This page is the receipt: every source behind the math, when it was last checked, and what we deliberately leave out.

Written & fact-checked by the PaycheckSmart editorial team (under the house byline Dana Reyes)Updated

Why this exists

Show the full breakdown, not a rounded guess

Most "paycheck calculators" either hide their assumptions or quietly skip lines like California SDI or the New York City resident tax, so the number they hand you is off. We built PaycheckSmart to show every line that comes out of your check, so you can see exactly where your money goes — and check our work against the same public documents we used.

Federal sources

The federal numbers, and where they come from

Federal income-tax withholding follows the IRS percentage method. Brackets and the standard deduction come from the IRS annual inflation-adjustment release; FICA rates and the Social Security wage base come from the IRS and the Social Security Administration. Each is linked below so you can verify any figure yourself.

State sources

Each state, from its own tax authority

For every state we cover, the rate, bracket, or "no income tax" status is taken from that state's own Department of Revenue, Franchise Tax Board, or Tax Department — not a secondary aggregator.

Our promises

How we keep it honest

  • Every result is labeled an estimate for a specific tax year, with a visible last-verified date.
  • The calculator runs entirely in your browser. We never see your salary and store nothing about you.
  • We are not affiliated with the IRS, the SSA, or any state tax agency, and this is not tax advice.
  • PaycheckSmart is written and fact-checked by our editorial team under a disclosed house byline — we do not claim licensed CPA or EA credentials.

The honest limits

What this calculator does not model

An accurate tool is honest about its edges. These situations can move your real paycheck away from our estimate, and we don't try to model them:

  • Additional per-paycheck withholding you request on your W-4 (Step 4c) or extra amounts your employer withholds.
  • Local/city income taxes other than the optional New York City resident tax — e.g. Yonkers, Ohio and Pennsylvania municipalities.
  • Post-tax deductions like Roth 401(k), garnishments, union dues, or after-tax insurance premiums.
  • State disability or paid-family-leave payroll taxes beyond California SDI (e.g. NY PFL, WA Cares).
  • Year-to-date effects: the Social Security wage-base cap and the extra Medicare threshold are applied on an annualized basis, not by tracking your running total across paychecks.
  • Bonuses taxed under the supplemental-wage flat rate, self-employment tax, and non-wage income.

Funding

How PaycheckSmart is funded

The calculators are free. To cover hosting and the work of keeping tax data current, we plan to display advertising and may include affiliate links in the future. Ads and affiliate links never change the math or what we show you. See our disclosure for details.

Talk to us

Get in touch

Spotted a number that looks off, or want your state added next? We genuinely want to hear it — reach us on our contact page.

Federal and state tax data last verified against the primary sources linked above.