A payroll week is a pay-period unit used by payroll systems to align cycles to weekly, fortnightly, or 4-weekly schedules. The week boundary determines when hours are cut off, when timesheets close, and when PAYG withholding is calculated.
Australian PAYG withholding
The Australian Taxation Office publishes PAYG withholding tax tables in 4 pay-period variants:
- Weekly — single payroll week.
- Fortnightly — 2 payroll weeks.
- Monthly — calendar month.
- 4-weekly — 4 payroll weeks, used by some award-based employers.
Employers select the table matching their pay cycle. Each table converts gross pay into the correct withholding amount for that period length, per ATO Schedule 1.
United States biweekly conventions
US payroll commonly runs biweekly — 26 pay periods per year — or semi-monthly — 24 pay periods per year. Biweekly aligns to payroll weeks and produces 3-paycheck months twice a year. Semi-monthly fixes paydays on calendar dates (typically the 15th and last day) and does not align to week boundaries.
Alignment to week-numbering standards
Payroll week start days vary by jurisdiction and standard:
- ISO 8601 — Monday start, used by most European payroll systems.
- US Standard — Sunday start, used by US payroll providers including ADP and Paychex.
- Australian financial year — vendor-dependent; Xero and MYOB default to Monday but allow configuration.
A 53-week ISO year produces a 53rd weekly pay run, requiring reconciliation against annualised salary assumptions that presume 52 weeks.