A six-on, three-off schedule repeats every nine days: six workdays followed by three rest days. Because nine is not a multiple of seven, the work and rest blocks move through the weekdays. Its average weekly hours depend on the length of each workday, not just the number of days worked.
Calculate the cycle average
Multiply six workdays by the net hours per workday to obtain cycle hours. Divide by nine calendar days and multiply by seven for the long-run weekly average. For eight-hour shifts, the calculation is 6 × 8 ÷ 9 × 7 = 37.3333 hours per week.
| Net shift length | Hours per nine-day cycle | Average hours per seven days |
|---|---|---|
| 8 hours | 48 | 37.3333 |
| 10 hours | 60 | 46.6667 |
| 12 hours | 72 | 56 |
These are mathematical averages, not claims that any pattern is appropriate or compliant for a particular role. They also do not represent the hours in every actual payroll week.
Understand why weekends move
If a cycle starts on Monday, the next cycle starts nine days later, on Wednesday. Each restart shifts two weekdays forward. After seven cycles, 63 days have passed and the starting weekday repeats. This 63-day horizon is useful when checking how work and rest days distribute across weekdays.
Do not assume that three days off means every weekend is free. Mark the actual dates and inspect Saturdays and Sundays. A schedule can have a regular number of rest days per cycle while giving very different weekends off from month to month.
Count a partial month explicitly
Suppose a 30-day reporting window begins on the first workday of the cycle. The first 27 days contain three complete cycles, or 18 shifts. The next three days are workdays in the fourth cycle, producing 21 shifts in that window. At eight hours per shift, that is 168 scheduled hours.
A different starting position in the cycle can produce a different count for the same 30-day length. That is why multiplying the long-run weekly average by a rough number of weeks is not a substitute for a dated calendar.
Separate the person pattern from service coverage
One employee's six-on, three-off pattern describes availability, not how many employees the service needs. For team coverage, assign each person's cycle offset and shift hours, then count simultaneous availability. Rest blocks that overlap across the team can create gaps even if total hours appear generous.
Keep leave, training and swaps as dated exceptions. Check whether a replacement changes the next cycle or only that occurrence. Publishing a calendar without this rule can leave different team members following different versions of the pattern.
Frequently asked questions
Is the average of 37.3333 hours a payroll total?
No. It describes the repeating pattern over time. Actual weekly hours depend on which six workdays fall inside the reporting boundary.
How long should a trial calendar be?
A 63-day calendar shows the full interaction between the nine-day cycle and the seven weekdays. Add the actual leave and closure dates for the period you are planning.
Related calculators and guides
- Rotating Shift Calendar
- Shift Coverage & Gap Calculator
- 4 On, 4 Off: Hours, Weekends and Calendar Drift
Explore more in Shift Schedules Calculators and Guides.