Waking up at the end of a sleep cycle feels much easier than waking from deep sleep. Choose your alarm time (or bedtime) to see the best times to sleep or wake.
Fill in the details and click Calculate to see your results.
Sleep runs in cycles of about 90 minutes — light sleep, deep sleep and dream (REM) sleep. Waking at the end of a cycle, rather than in the middle of deep sleep, leaves you less groggy.
Adults need 7–9 hours a night: 5 or 6 full cycles. The calculator adds the time you usually take to fall asleep (15 minutes by default) and lists the best times.
| I want to | Wake up at a set time — when should I sleep? |
| Time | 6:30 AM |
| Minutes to fall asleep | 15 min |
| Your age | 30 years |
| Go to bed at | 9:15 PM or 10:45 PM |
| Sleep you need at 30 | 7–9 h |
| Time to fall asleep allowed | 15 min |
Go to bed at 9:15 PM or 10:45 PM.
| I want to | Go to bed now / at a time — when should I wake? |
| Time | 11:00 PM |
| Minutes to fall asleep | 15 min |
| Your age | 25 years |
| Set your alarm for | 8:15 AM or 6:45 AM |
| Sleep you need at 25 | 7–9 h |
| Time to fall asleep allowed | 15 min |
Set the alarm for 8:15 AM or 6:45 AM.
With 15 minutes to fall asleep, go to bed at 8:45 pm (6 cycles, 9 h) or 10:15 pm (5 cycles, 7.5 h).
Adults 7–9 hours, teenagers 8–10, children 6–12 years 9–12, and adults over 65 7–8 hours (AASM / National Sleep Foundation).
They vary from about 70 to 120 minutes between people and through the night, so treat the times as a guide and adjust by 15–20 minutes if needed.