Twenty-four hours on duty, then seventy-two off, on a four-day cycle. One tour, then three clear days before the next shift change. It is the same shift-day structure as a 24/48 with one more day off attached to the end.
These are example times, not your times. Everything below is computed from a single pair of wake anchors: 6:30 AM on a work day and 7:30 AM on a rest day. A 6:30 AM wake puts you at an 0830 shift change, and a 7:30 AM rest anchor is close enough that two clear days will not open a gap. If your anchors are different, every window below shifts with them, which is what the plan builder does with your own numbers.
The plan works backward from the wake anchor rather than forward from bedtime, because bedtime is the part your schedule takes away from you. The sleep target on each day is the anchor minus the sleep opportunity; the caffeine cutoff is eight hours before that target; the last real meal is three hours before wind-down starts. So the anchor is the only number you set, and the rest falls out of it.
The 24 you are on duty. 24 hours on duty, going on the tour at 8:30 AM.
| Wake anchor | 6:30 AM |
|---|---|
| Bright light | 6:30 AM to 8:00 AM |
| Caffeine | 7:30 AM to 8:00 AM (first cup), stop by 2:30 PM |
| Planned nap | 10:30 AM to 12:00 PM |
| Last real meal | by 6:00 PM |
| Wind-down | 9:00 PM to 9:30 PM |
| Sleep target | 10:30 PM |
The day you come off the 24.
| Wake anchor | 6:30 AM |
|---|---|
| Bright light | 6:30 AM to 8:00 AM |
| Caffeine | 7:30 AM to 8:00 AM (first cup), stop by 4:30 PM |
| Planned nap | 10:30 AM to 12:00 PM |
| Last real meal | by 8:00 PM |
| Wind-down | 11:00 PM to 11:30 PM |
| Sleep target | 12:30 AM |
The two clear days before you go back.
| Wake anchor | 7:30 AM |
|---|---|
| Bright light | 7:30 AM to 9:00 AM |
| Caffeine | 8:30 AM to 9:00 AM (first cup), stop by 3:30 PM |
| Last real meal | by 7:00 PM |
| Wind-down | 10:00 PM to 10:30 PM |
| Sleep target | 11:30 PM |
Three days off is enough room to drift, and drift is the failure mode this pattern has instead of exhaustion. The recovery day works the same as it does on a 24/48 — a shorter sleep aligned to the shift anchor, a planned nap, an early night — but after that there are two full days with nothing holding the anchor in place. Let it slide an hour a day and the last day off ends two hours from where the next shift change needs you. That is a bad first tour built entirely out of good days off.
The recovery day off the 24 works the same as on a 24/48: short aligned sleep, a planned nap, early night. The difference is you get two clear days after it, so let the rest-day anchor hold for both instead of drifting later each day. Drifting is what turns the last day off into a bad first shift.
Eight hours before the sleep opportunity you are protecting. In the worked example on this page, a 6:30 AM wake anchor on a work day puts the sleep target at 10:30 PM, so the last caffeine of any kind lands at 2:30 PM. Move the anchor and the cutoff moves with it — the eight hours is the rule, not the clock time.
The plan sets the sleep target backward from the wake anchor rather than forward from the end of a shift. In the example here, a 6:30 AM work-day anchor gives a 10:30 PM sleep target, with wind-down starting at 9:00 PM. On a rest day the 7:30 AM anchor gives an 11:30 PM target.
Within 90 minutes of waking, whatever the sun is doing. In the worked example that is 6:30 AM to 8:00 AM on a work day. Ten to fifteen minutes is enough. Then keep bright light off you in the three hours before the sleep target.
One nap, taken on purpose, four to five and a half hours after waking — 10:30 AM to 12:00 PM in the worked example on this page. Twenty to thirty minutes, or a full ninety. Anything in between leaves you groggy.
Recovery day is planned as its own kind of day rather than a normal one. In the example, it runs on a shorter sleep opportunity ending at 6:30 AM, with the caffeine cutoff at 4:30 PM and the last real meal by 8:00 PM.
The plan builder takes six questions — your pattern, your two wake times, your last cup of coffee — and computes the same windows against the schedule you actually work, as a visual timeline for each kind of day. Free, printable, no account.
Build my free sleep planEvery window on this page comes from one of a handful of rules, and the Shift Worker's Field Manual is where those rules are laid out with their sources: why the wake anchor is the lever rather than bedtime, what light does to the body clock and when, the eight-hour caffeine cutoff and where it comes from, and what to do when the problem is bigger than a schedule.
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