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2026 federal rules

How one pay period becomes the result

The method annualizes federal taxable wages, applies W-4 adjustments, selects the 2026 schedule, converts back to the pay period and calculates FICA separately.

Federal income-tax withholding

  1. Subtract the entered deductions that payroll treats as reducing federal income-tax wages.
  2. Multiply the period amount by the pay periods in the year.
  3. Add W-4 Step 4(a), subtract Step 4(b), and subtract $12,900 for married filing jointly or $8,600 otherwise when Step 2(c) is not checked.
  4. Apply the 2026 annual percentage schedule for filing status and Step 2(c).
  5. Divide the tentative annual withholding by periods, subtract Step 3 credits divided by periods, then add Step 4(c) extra withholding.
period FIT = max(0, annual schedule ÷ periods − Step 3 ÷ periods) + Step 4(c)

FICA

For 2026, employee and employer Social Security are each 6.2% up to $184,500 of annual Social Security wages. Employee and employer Medicare are each 1.45% without a wage base. Employee Additional Medicare withholding is 0.9% on wages paid above $200,000 in the calendar year; there is no employer match.

Rounding

The calculator keeps calculations unrounded until each displayed tax line, then rounds the line and reconciliation to the nearest cent. We check ordinary amounts, zero values, invalid inputs, and the points where wage limits begin or end.