Why 12-hour schedules use four crews
Round-the-clock coverage with two shifts a day means 14 shifts a week to fill. Four crews working half the days of the year, about 3.5 shifts a week each, fill exactly that. Every rotation below comes to 42 hours a week, 182 or 183 shifts and about 2,190 hours a year.
The four common 12-hour rotations
They share crew count and average hours. They differ in how the time is grouped:
- DuPont: 28-day cycle of 4 nights, 3 off, 3 days, 1 off, 3 nights, 3 off, 4 days, 7 off. Up to 4 shifts in a row and one 7-day break per cycle.
- 2-2-3: 14-day rhythm of 2 on, 2 off, 3 on, 2 off, 2 on, 3 off, run on days and then on nights. Never more than 3 in a row or 3 off.
- Pitman: the same 14-day rhythm with fixed crews, two on days and two on nights.
- 4 on 4 off: 4 shifts, 4 days off, repeating. In the version shown here, the next 4 shifts are nights, so the full cycle is 16 days.
How to choose a 12-hour rotation
Start with what your people complain about. If they want long breaks, DuPont's 7 days off is the draw, but plan for the 72-hour week. If long stretches wear them out, Pitman and 2-2-3 cap work at 3 days. If some people should never rotate to nights, use a fixed Pitman. If you want one rule anyone can remember, use 4 on 4 off.
Then check weekends and pay. The weekday the cycle starts on decides which weekends are off, and the day your payroll week starts decides how many hours count as overtime.
Overtime on 12-hour shifts
Federal law counts overtime by the workweek, not the day: non-exempt employees earn time and a half after 40 hours in a workweek. Every 12-hour rotation includes 48-hour weeks, so overtime is part of the budget. Some states add daily rules; California, for example, requires overtime after 8 hours in a workday.
The cost of 12-hour shifts
NIOSH research links 12-hour shifts to lower alertness, less sleep and disruption of life outside work, and shift work in general to sleep and metabolic problems. NIOSH suggests at least 11 hours between shifts and some weekends off.
Pros and cons
- Two handovers a day instead of three.
- About half the days of the year are off.
- Longer blocks of time off than a 5-day, 8-hour week.
- Four crews cover 24/7 with no gaps.
- Long days: 12 hours plus commute leaves little time on work days.
- Lower alertness late in the shift, according to NIOSH.
- 48-hour weeks mean overtime under the 40-hour rule; California also counts daily overtime.
- A missed shift leaves a 12-hour hole to fill.
Who it works for
- Hospitals and emergency rooms
- Police, fire and EMS
- Manufacturing and process plants
- Utilities and energy
- Security
FAQ
What is a 12-hour shift schedule?
A schedule where each shift lasts 12 hours, usually one day shift and one night shift, so two shifts cover 24 hours. Teams that run 24/7 put four crews on a rotation such as DuPont, 2-2-3, Pitman or 4 on 4 off.
What is the best 12-hour shift schedule?
It depends on what your team values. DuPont gives a 7-day break every 4 weeks. Pitman and 2-2-3 keep stretches to 3 days. 4 on 4 off is the easiest to remember. All four average 42 hours a week.
How many days a week do you work on 12-hour shifts?
3 or 4 in most weeks, 3.5 on average. That's about 182 or 183 shifts a year.
How many crews do you need for 12-hour shifts 7 days a week?
Four crews for 24/7. If you only cover daytime, 7 days a week, two crews on a 2-2-3 or Pitman rhythm are enough.
What time do 12-hour shifts start?
7am to 7pm and 7pm to 7am are common, and 6am to 6pm is another option. NIOSH notes that start times of 6am or earlier tend to shorten sleep.
Do you get overtime for a 12-hour shift?
Under federal law, only for hours over 40 in a workweek, not per day. Some states differ: California requires overtime after 8 hours in a day.