Sleep Cycle Calculator
Waking up mid-cycle is why some mornings feel brutal. Pick when you need to wake up (or when you're going to bed) and get times that line up with roughly 90-minute sleep cycles.
Go to bed for 6 cycles (9.0 h sleep)9:45 PM
- Go to bed for 5 cycles (7.5 h sleep)
- 11:15 PM
- Go to bed for 4 cycles (6.0 h sleep)
- 12:45 AM
Bedtimes for common wake-up times
Allowing 15 minutes to fall asleep:
| Wake up at | Bed for 9 h | Bed for 7.5 h |
|---|---|---|
| 5:30 AM | 8:15 PM | 9:45 PM |
| 6:00 AM | 8:45 PM | 10:15 PM |
| 6:30 AM | 9:15 PM | 10:45 PM |
| 7:00 AM | 9:45 PM | 11:15 PM |
| 7:30 AM | 10:15 PM | 11:45 PM |
| 8:00 AM | 10:45 PM | 12:15 AM |
How it works
Sleep runs in cycles of roughly 90 minutes. Waking at the end of a cycle tends to feel easier than waking in the middle of one.
Cycle length varies from person to person, so treat these times as a starting point and adjust.
Tips
- Keep the same wake-up time every day, including weekends.
- Screens and caffeine late at night make it harder to fall asleep on time.
Frequently asked questions
How many cycles do I need?
Most adults do best with about 5 to 6 cycles (7.5 to 9 hours). Fewer than that is a rough night.
General information only — not medical advice.