How the Massachusetts estimate works
Enter gross pay for one pay period, federal W-4 adjustments, and the state details shown above. Federal withholding follows Publication 15-T. Massachusetts Circular M first subtracts the current FICA and Medicare deduction while the annual $2,000 limit remains, then subtracts the M-4 exemption factor. It annualizes the remaining wages, applies 5% through the 2026 $1,107,750 threshold and 9% above it, returns the result to the pay period, and applies the M-4 head-of-household, blindness, and additional-withholding adjustments. PFML is shown as a separate employee deduction when applicable.
Example: For $1,000 of weekly wages, one M-4 exemption, and $76.50 of current FICA and Medicare within the annual deduction limit, Circular M leaves $838.50 before annualization. The 5% calculation is $41.93 per week before any head-of-household, blindness, or additional-withholding adjustment. The calculator does not assume any unentered benefit deduction or invent a tax result.
Weekly, biweekly, semimonthly, and monthly are the supported paycheck frequencies. “Annual salary” is an earnings input and the annual view is a simple period multiplication; neither is an annual payroll-period method. The special Form W-4 adjustment for nonresident aliens is not modeled.