On a 12-hour shift, you can still fit 7.5 hours of sleep (5 cycles) between shifts as long as your commute is an hour or less each way. On nights, that means lights out within an hour of getting home. On days, it means being in bed by about 10 PM. The hard part is protecting that window on back-to-back shifts, when there's almost no slack.
Nurses, paramedics, police, firefighters and plant workers on 12s tend to run short. One study that tracked hospital nurses across three 12-hour shifts in a row measured an average of just 5.5 hours of sleep between shifts, and the nurses got sleepier with each shift.
The tables below use the same math as the shift work sleep calculator: 30 minutes to wind down after you get home, 15 minutes to fall asleep, 90-minute cycles, and 45 minutes to get ready before you leave.
Free toolShift Work Sleep CalculatorWhen to sleep and stop caffeine around any shift, including nights.7 PM to 7 AM night shift schedule
| Commute each way | Lights out | Wake after 5 cycles | Up by (latest) | Most cycles that fit | Last coffee |
|---|---|---|---|---|---|
| 0 min | 7:30 AM | 3:15 PM | 6:15 PM | 7 | 9:50 PM |
| 15 min | 7:45 AM | 3:30 PM | 6:00 PM | 6 | 10:05 PM |
| 30 min | 8:00 AM | 3:45 PM | 5:45 PM | 6 | 10:20 PM |
| 45 min | 8:15 AM | 4:00 PM | 5:30 PM | 6 | 10:35 PM |
| 60 min | 8:30 AM | 4:15 PM | 5:15 PM | 5 | 10:50 PM |
"Last coffee" is for a regular 8 oz cup (about 95 mg), timed so it's down to about 25 mg by lights out, using an average 5-hour half-life. That puts your cutoff within the first 3 to 4 hours of the shift. For the room setup and household rules that make day sleep work, see how to sleep during the day after a night shift.
7 AM to 7 PM day shift schedule
Day shifts flip the problem. You have plenty of time overnight, but the start is early, so the key number is the latest time you can go to bed and still get 5 full cycles.
| Commute each way | Home by | Lights out for 5 cycles | Lights out for 6 cycles | Up by | Last coffee (5-cycle bedtime) |
|---|---|---|---|---|---|
| 0 min | 7:00 PM | 10:30 PM | 9:00 PM | 6:15 AM | 12:50 PM |
| 15 min | 7:15 PM | 10:15 PM | 8:45 PM | 6:00 AM | 12:35 PM |
| 30 min | 7:30 PM | 10:00 PM | 8:30 PM | 5:45 AM | 12:20 PM |
| 45 min | 7:45 PM | 9:45 PM | 8:15 PM | 5:30 AM | 12:05 PM |
| 60 min | 8:00 PM | 9:30 PM | 8:00 PM | 5:15 AM | 11:50 AM |
With a one-hour commute, you get just 90 minutes at home before lights out on a work night. That's why long-commute day workers often feel like they do nothing but work and sleep. Plan meals ahead and keep screens out of that last half hour.
The shift work sleep calculator starts your sleep as soon as you're home and wound down. On day shifts you can go to bed any time up to the "lights out for 5 cycles" column and still get a full 7.5 hours.
When you only have 10 hours between shifts
Overtime and handover delays can shrink your break fast. Here's a day shift that ran late to 9 PM, with the next shift starting at 7 AM, leaving 10 hours between them.
| Commute each way | Lights out | Cycles that fit | Wake up | Sleep |
|---|---|---|---|---|
| 0 min | 9:30 PM | 5 | 5:15 AM | 7.5 h |
| 15 min | 9:45 PM | 5 | 5:30 AM | 7.5 h |
| 30 min | 10:00 PM | 5 | 5:45 AM | 7.5 h |
| 45 min | 10:15 PM | 4 | 4:30 AM | 6 h |
| 60 min | 10:30 PM | 4 | 4:45 AM | 6 h |
These assume you go almost straight to bed. Every extra 30 minutes for dinner, a shower or a scroll comes out of your sleep, and once you lose a full cycle you're down to 6 hours. On a 10-hour turnaround:
- Eat at work before you leave, or have something ready at home.
- Lay out clothes and pack food for the next shift before bed.
- Skip the wind-down scroll. Phone on the charger across the room.
- If only 4 cycles fit, plan a 20-minute nap on your next break. The guide to napping at work covers how to do it safely.
Back-to-back 12s: keeping the run together
Three or four 12s in a row is where sleep debt builds. Losing even an hour a night adds up to a big shortfall by the last shift.
- Keep the same sleep window every work day. Consistency helps your body clock more than any single long sleep.
- Nap before the first night shift. A 20-minute or 90-minute nap in the late afternoon can help you through the first night, when you've usually been awake since morning.
- Protect caffeine timing, especially by the third or fourth shift, when it's tempting to have more later.
- Don't try to catch up by sleeping all day on your first day off. It makes the switch harder. See how to switch from night shift to days.
- Track your shortfall with the sleep debt calculator if the runs are leaving you wrecked.
The commute is part of the shift
After 12 hours, the drive home can be the most dangerous part of the day, especially after nights. If you're yawning, drifting or missing exits, pull over somewhere safe for a 20-minute nap, or get a ride.
If you're regularly sleeping badly between shifts, falling asleep at work, or having trouble staying awake while driving, talk to a doctor. Ongoing insomnia or heavy sleepiness linked to your shifts can be a sign of shift work disorder, which is treatable.