How to Calculate Monthly Work Hours
Monthly work hours vary with the number of workdays, the schedule, holidays, leave, and unpaid breaks. For an accurate timesheet, add the actual net hours worked during the month. For planning, use the expected workdays and daily hours.
Practical timekeeping guide · ShiftHours
Calculate actual monthly hours
Add the net duration of every shift in the calendar month. For example, if your recorded daily totals add up to 168 hours, that is your actual monthly work-hour total for the records included.
This method is more accurate than assuming every month contains the same number of workdays.
Estimate from a standard schedule
For a rough planning estimate, multiply expected workdays by net hours per day. If a schedule has 20 workdays at 7.5 net hours per day, the estimate is 150 hours. Adjust for holidays, leave, overtime, and schedule changes.
Label an estimate clearly so it is not confused with a verified timesheet total.
Avoid a fixed monthly assumption
Months have different lengths and weekdays. A five-day schedule may contain a different number of scheduled workdays each month. Payroll periods may also use fixed cut-off dates that do not match the calendar month.
Use the period dates specified by your employer or project.
Build a monthly summary
Track daily shifts and weekly subtotals, then add the totals for the month. The ShiftHours weekly calculator can help with daily calculations, while you can combine verified weekly totals for a monthly report.
Use the free ShiftHours work hours calculator to calculate shift length, subtract unpaid breaks, and view decimal hours. For weekly totals, try the weekly calculator.
Worked example: estimate a month
If a schedule averages 40 hours per week, multiplying by 4 gives a rough 160-hour four-week estimate. A calendar month is not always exactly four weeks, so for an accurate monthly total, add the actual recorded shifts in that month.
Related resources
Open the work hours calculator · Browse all ShiftHours articles · Decimal hours chart