How Pay Frequency Changes Your Tax Withholding

Why frequency matters

Income tax withholding is figured by annualizing a paycheck — the system multiplies the check by the number of pay periods in a year, applies the annual brackets and standard deduction, then divides back down. Weekly pay annualizes over 52 periods, biweekly over 26, semimonthly over 24, and monthly over 12. Same check amount, very different annual figure.

A worked example

Take a single employee with a $625 check and a standard 2026 W-4. Paid weekly, that annualizes to $32,500 — well above the $16,100 standard deduction — so federal withholding is about $33 per check. Paid biweekly, the same $625 annualizes to only $16,250, barely above the standard deduction, so withholding is about $0.58 per check.

Both are correct. The weekly employee simply earns twice as much over the year, so more of it is taxable and more is withheld each period. Neither is a bug — they are just different schedules.

It changes timing, not what you owe

Pay frequency changes how withholding is spread across the year, not the employee’s actual tax liability. Someone who is under-withheld because of a low-wage schedule simply settles up at filing (or can add extra withholding on their W-4). The important thing is that both your payroll system and any system you compare against are set to the same frequency before you read anything into the numbers.

Switching schedules in Payrollix

You can set or change an employee or company between weekly, biweekly, semimonthly, and monthly, and the withholding recalculates on the new schedule automatically. Changing frequency only affects future pay periods — already-processed payrolls are never altered.