Shift Schedule Calculator – Plan Rotating Work Schedules
Shift workers, HR planners, and operations managers all face the same recurring questions: which shift am I working on a given date, how many hours will I clock this pay period, and what does the team's rotation look like next month. The Shift Schedule Calculator answers all three by turning a rotation pattern and a start date into a full projected calendar, complete with hour and shift totals.
Built-In Rotation Templates
Manufacturing plants, hospitals, emergency services, security firms, and call centers each tend to standardize on a handful of well-known rotation shapes. This calculator ships with 4-on-4-off, 3-on-3-off, DuPont (a 28-day, 4-crew cycle averaging a 42-hour week), Pitman (the 2-2-3 pattern that guarantees every other weekend off), Panama (two stacked 2-2-3 blocks that swap from day to night shifts), and Continental (a fast 2-2-4 rotation mixing day and night shifts). A Fixed Weekday mode is also available for traditional non-rotating schedules like Monday through Friday.
Custom On/Off Cycles
Not every workplace follows a named industry pattern. Choosing Custom lets you define any cycle by entering the number of consecutive on-days and off-days — for example 7 on / 7 off for an offshore or FIFO roster, or 2 on / 3 off for a lighter part-time rotation.
How the Projection Works
Every rotation, whether preset or custom, is represented internally as a repeating array of on/off day states. For each date in your projection range, the calculator counts the number of days since the Schedule Start Date, takes that count modulo the cycle length, and looks up the corresponding day state. This daysBetween(start, date) mod cycleLength approach correctly handles dates both after and before the start date, so you can check past shifts as easily as future ones.
Hours, Overtime, and Next Shift
Once the calendar is generated, the calculator sums Total Scheduled Hours, Total Scheduled Shifts, and Total Days Off across the range, and derives the Average Weekly Hours. If you set a weekly Overtime Threshold, hours are grouped into ISO calendar weeks (Monday–Sunday) and any hours beyond the threshold in a given week are reported as overtime. The Next Shift panel highlights the closest upcoming on-shift date so you always know when you're due back.
Holidays and Export
Add a list of public or company holiday dates to flag them directly on the shift calendar without affecting the underlying rotation math. When you're done, use Copy Result for a quick text summary or Download CSV to export the full date-by-date schedule — including weekday, on/off status, shift label, hours, and holiday flag — for use in a spreadsheet or another planning tool.
Limitations
Published rotation definitions like DuPont and Panama can vary slightly between industries and employers. Treat the built-in presets as accurate references for the commonly cited pattern, but always confirm the exact cycle and official start date against your employer's schedule before relying on it for pay or attendance decisions.