Formula and assumptions
Each calendar day is mapped to a repeating work/rest pattern beginning on the selected cycle date.
Results depend on your inputs. Read the calculation methodology.
Rotating Shift Calendar
Build a 4-on/4-off, 2-2-3, DuPont work/rest or custom calendar with scheduled hours and an ICS download.
Worked example
A 4-on/4-off schedule repeats eight days: four workdays followed by four rest days.
Understand the result
Shift Schedules · Pillar guide
Rotating Shift Schedules: Patterns, Hours and Calendars
Understand how repeating shift rotations work and generate a calendar from a pattern and cycle start date.
Shift Schedules · Guide2-2-3 Schedule: A 14-Day Work and Rest Calendar
A common 2-2-3 work/rest cycle is two workdays, two rest days, three workdays, two rest days, two workdays and three rest days.
Shift Schedules · Guide4 On, 4 Off: Hours, Weekends and Calendar Drift
Four on, four off repeats every eight days. At twelve hours per workday, it averages 42 scheduled hours per seven-day week.
Shift Schedules · GuideDuPont Schedule: Reading a 28-Day Work/Rest Cycle
The work/rest version modeled here uses 4 work, 3 rest, 3 work, 1 rest, 3 work, 3 rest, 4 work and 7 rest days.
Related calculators
Hours & Pay
Work Hours Calculator
Add clock-in and clock-out times, subtract breaks, and see regular and overtime hours.
Calculate →Hours & PayShift Differential Calculator
Estimate extra pay from night, evening, weekend or other premium hours.
Calculate →PTOPTO Accrual Calculator
Calculate PTO earned per pay period and project an available balance.
Calculate →Workforce PlanningShift Coverage & Gap Calculator
Compare shift rows against a constant staffing target and see exactly when coverage falls short.
Calculate →Build the calendar from a known roster date
Choose the work/rest pattern, then anchor day one to a date you can verify. In a custom pattern, 1 marks a workday and 0 marks a rest day. The eight-day pattern 11110000 represents four on, four off. Moving the anchor by one day moves every future work marker, so compare several dates with the official roster before exporting.
Use the date range, not an annual shortcut
For a specific month, count only the work markers that fall inside that month. A 12-hour pattern with 15 workdays produces 180 scheduled hours. A long-run weekly average can be helpful for comparison, but it is not the actual total for every month or payroll week. The export contains all-day markers, not timed day/night assignments.
Frequently asked questions
How many hours is a 2-2-3 schedule?
The modeled 14-day work/rest pattern has seven workdays. Seven 12-hour shifts total 84 hours, averaging 42 per week. Individual workweeks can differ from that average.
Why do my four-on/four-off days move each week?
The rotation is eight days long while a calendar week is seven. Its start shifts through the weekdays; repeating a fixed weekly template will eventually show the wrong dates.
Will an imported calendar update automatically?
No. An ICS download is a snapshot. If the roster changes, generate a new file and replace the old imported calendar to avoid duplicate events.
Does this assign crews or day and night shifts?
No. It marks one person’s repeating work/rest dates. Confirm crew offsets, start times, rest requirements and any swaps in the employer’s official roster.