4 on 4 off is an 8-day cycle: four 12-hour shifts, then four days off, repeat. Because the cycle is one day longer than the week, every block starts one weekday later than the last. Your Monday start becomes a Tuesday start, then a Wednesday start, and around it goes all year. That drift shapes everything else about the pattern.
We make Lumical, an app that scans work rosters into your calendar, so read this with that in mind. Everything below is calendar math you can verify on our free shift pattern visualizer.
The drift is the feature
A rotation like 2-2-3 is 14 days long, divides evenly into weeks, and locks every crew to the same weekdays all year: one alignment gets 26 full weekends off, another gets none. 4 on 4 off cannot lock. The one-day slide walks your off-block through every position in the week over eight cycles, so the good and bad weekends spread across every crew.
The 2026 numbers, counting a full weekend off as one where no shift touches Saturday or Sunday:
- On day shifts, every starting position lands between 18 and 21 full weekends off. The average is 19.5.
- On nights, the range is 12 to 14, average 13. Nights lose more because a Friday night shift runs into Saturday morning and spoils that weekend. More on that in the Friday night rule.
No crew gets lucky and none gets stuck. Compare that with a Monday to Friday job, which keeps all 52 weekends, or with the locked rotations where the answer is 26 or 0 forever.
Annual hours: where the 42 comes from
Four 12-hour shifts per 8 days is 48 hours per cycle. Scale that to a 7-day week and you get 42, which is why contracts quote 4 on 4 off as a nominal 42-hour week. No single week actually contains 42 hours. Any calendar week holds three or four of your shifts, so you work 36 hours some weeks and 48 in others, and only the average is 42.
Over the 365 days of 2026 the drift means:
- 181 to 184 shifts depending on your starting position, 182.5 on average
- 2,172 to 2,208 hours, 2,190 on average
If your own count and your contract disagree by a shift or two, this is why: no calendar year contains a whole number of 8-day cycles.
When a calendar beats the math
You do not need to memorize any of this. The 4 on 4 off calendar for 2026 lays out the full year for any starting position, and the 2027 calendar is there when your roster rolls over. The interactive visualizer also charts 4 on 4 off against Pitman, DuPont, and the rest on full weekends off, and exports the comparison as a PNG.
Where an app earns its place
Fair is fair: a clean 4 on 4 off runs on autopilot, and a paper year planner covers it if you sit down once and mark out the drift. The trouble is the real version: a swap here, overtime there, a training day mid-block, all delivered as a photographed grid. Lumical reads that photo, understands the rotation, and files every shift on the correct days, overnights included. You review everything before it saves.
Working 4 on 4 off from a printed roster? Get Lumical on the App Store and put the whole month in your calendar from one photo.