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.
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.
- IRS Publication 15-T (Percentage Method)
The federal income-tax withholding method our engine mirrors.
- IRS Rev. Proc. 2025-32 (2026 inflation adjustments)
2026 tax brackets and the standard deduction.
- SSA 2026 COLA / wage-base announcement
The Social Security wage base and 6.2% employee rate.
- IRS: Additional Medicare Tax
The 1.45% Medicare rate and the extra 0.9% over $200,000.
State sources
Every state and DC, with its source and verified date
For 47of the 51 jurisdictions, the state calculation follows the state's own 2026 employer withholding publication (its formula, allowances and tables), checked against the worked examples or table rows printed in that publication; the table below links each one. Where a state's withholding method differs from its return schedule, the state page says so. The remaining states still use the Tax Foundation's 2026 state income tax data and carry a visible "not yet verified" notice on their pages until they are reconciled.
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 and city income taxes other than the optional New York City resident tax (for example Ohio and Pennsylvania municipalities, Maryland and Indiana counties, Kentucky and Michigan cities, and Missouri's Kansas City/St. Louis earnings taxes). Each affected state page discloses this.
- 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, Washington PFML and WA Cares, Oregon Paid Leave).
- 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 some links on the site are affiliate links. 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.