Start with the number that settles most arguments: covering 24 hours a day, seven days a week takes 168 hours of somebody's time. Split that between four teams and each one works 42 hours a week. Every 12-hour pattern in this guide lands on 42, because the arithmetic leaves nowhere else to land. What the patterns actually differ on is how those hours are arranged, and that is what people feel.
The four at a glance
| Pattern | Cycle | Teams | Avg hours/week | Longest break |
|---|---|---|---|---|
| 4 on 4 off | 8 days | 4 | 42 | 4 days |
| Panama (2-2-3) | 14 days | 4 | 42 | 3 days |
| DuPont | 28 days | 4 | 42 | 7 days |
| Continental (2-2-4) | 8 days | 4 | 42 | 4 days |
4 on 4 off
Four 12-hour shifts, then four days off, repeating on an eight-day cycle. The simplest of the four to explain and the easiest to remember, because the block length never changes.
The eight-day cycle does not line up with a seven-day week, so the pattern walks across the calendar: this block is Monday to Thursday, the next is Friday to Monday. Your days off are never the same weekdays twice in a row, and you work roughly half of all weekends.
Suits: teams that value long, predictable rest blocks and do not need fixed weekdays. Full guide and a calculator for any month.