Shift Pattern Calculator

How This Calculator Works

Enter the date of any day that starts a working stretch for you — for example, the first of your 4 consecutive on-days in a 4 on 4 off rotation, or the first night shift in a DuPont cycle. The calculator treats that date as day one of your rotation and projects the recurring pattern forward, marking every day as either a work day or an off day. It doesn't need your employer's master roster or crew letter — just one known working day is enough to reconstruct the whole cycle going forward.

The Four Patterns Explained

4 on 4 off is an 8-day cycle: 4 consecutive work days (typically 12-hour shifts), then 4 consecutive days off, repeating indefinitely. It's common in manufacturing, security, warehousing, and healthcare, and gives a simple, predictable rhythm with no day/night alternation built in.

DuPont is a 4-crew, 28-day rotation using 12-hour shifts. A single crew's cycle runs 4 night shifts, 3 off, 3 day shifts, 4 off, 4 night shifts, 3 off, then a stretch of 7 consecutive day shifts before the cycle repeats — which means every crew gets one full week off every four weeks.

Pitman is a 4-crew, 14-day rotation, also on 12-hour shifts, built around a 2-on/2-off/3-on/2-off/2-on/3-off pattern. It averages 7 working days out of every 14, with an alternating 3-day weekend every other week.

2-2-3 (Panama) follows the same 2-on/2-off/3-on/2-off/2-on/3-off structure as Pitman over a 14-day span, but is typically described with every-other-weekend off — employees work 2 days, rest 2, work 3, rest 2, work 2, rest 3, and repeat, again averaging 7 working days per 14.

Comparing the Four Patterns

Pattern	Cycle Length	Work/Off Split	Typical Shift Length
4 on 4 off	8 days	4 on / 4 off	12 hours
DuPont	28 days	18 on / 10 off	12 hours
Pitman	14 days	7 on / 7 off	12 hours
2-2-3 (Panama)	14 days	7 on / 7 off	12 hours

This calculator tracks on/off status only — it doesn't distinguish day shift from night shift, since that alternation is usually set by your employer's specific roster and varies between DuPont/Pitman implementations. Use it to plan around your days off, then confirm shift timing against your actual schedule.

Choosing Between These Patterns

If you're comparing rotations rather than just checking your own schedule, the main tradeoff is predictability versus recovery time. 4 on 4 off is the simplest to plan around since every block is identical, but four consecutive 12-hour shifts back to back can be demanding without a day/night split. Pitman and 2-2-3 spread the same weekly average (7 on, 7 off per fortnight) across shorter 2-3 day blocks, which most shift workers find easier to sustain, at the cost of a less uniform weekly rhythm. DuPont's headline feature is the built-in full week off every 28 days, which appeals to workers who value one long recovery stretch over more frequent short breaks — but it also includes the longest single work stretch of the four (7 consecutive day shifts).

None of these patterns account for shift-length variations (8-hour vs. 12-hour), mandatory overtime, or holiday pay differentials, all of which vary by employer and industry — treat this tool as a planning aid for your own days off, not a substitute for your official roster.