How we calculate

The rules, sources and assumptions behind every NetPayCal result.

United States

  1. Gross pay is converted to an annual amount using your pay period, hours per week and paid weeks per year.
  2. Pre-tax 401(k) contributions and pre-tax health premiums are subtracted.
  3. Federal taxable income is pay after those deductions minus the 2026 standard deduction ($16,100 single, $32,200 married filing jointly, $24,150 head of household). We do not model itemized deductions.
  4. Federal tax uses the 2026 brackets for your filing status. The child tax credit of $2,200 per child under 17 is applied against tax, reduced by $50 per $1,000 of income above $200,000 ($400,000 married filing jointly). We do not include the refundable portion.
  5. Social Security is 6.2% of wages up to $184,500. Medicare is 1.45% of all wages plus 0.9% above the additional Medicare threshold. Pre-tax health premiums are excluded from FICA wages; 401(k) contributions are not.
  6. State tax applies each state’s published brackets or flat rate, standard deduction, exemptions and credits. For married couples filing jointly we use the state’s joint brackets where we hold them, otherwise doubled single brackets.
  7. State payroll contributions are included for California (SDI), New York (PFL and SDI), Washington (WA Cares and PFML) and Oregon (transit tax and Paid Leave Oregon). Maryland includes an average county income tax.

Not yet included

  • City and county income taxes outside Maryland (for example New York City, Philadelphia, Ohio municipalities, Indiana counties).
  • New Jersey and other state unemployment, disability or family-leave contributions not listed above.
  • Itemized deductions, tax credits other than the child tax credit, and supplemental-wage withholding on bonuses.

United Kingdom

  1. Pension salary sacrifice is taken from gross pay first.
  2. The personal allowance is £12,570, reduced by £1 for every £2 over £100,000 (tax code 1257L).
  3. Income tax uses the 2026/27 bands for England, Wales and Northern Ireland, or the Scottish bands set at the Scottish Budget on 13 January 2026.
  4. Class 1 employee National Insurance is 8% between £12,570 and £50,270, then 2%.
  5. Student loans use the 2026/27 thresholds: Plan 1 £26,900, Plan 2 £29,385, Plan 4 £33,795, Plan 5 £25,000 and Postgraduate £21,000.

Sources

IRS, Social Security Administration, U.S. Bureau of Labor Statistics, U.S. Department of Labor, state revenue departments, HMRC and GOV.UK, and the Scottish Government.

Accuracy

Results are estimates. Your employer’s payroll may differ because of your W-4 or tax code, benefits, local taxes and pay-date timing. If you find a figure that looks wrong, please tell us.