When should I wake up?
Enter what time you plan to go to bed, and we'll calculate the best times to wake up to feel refreshed.
Best times to wake up:
When should I go to bed?
Enter what time you need to wake up, and we'll calculate the best times to go to bed.
Best times to go to bed:
How the Sleep Calculator Works
Sleep occurs in cycles of approximately 90 minutes each. During each cycle, you progress through light sleep, deep sleep, and REM sleep. Waking up at the end of a complete cycle—during light sleep—leaves you feeling refreshed. Waking mid-cycle, especially during deep sleep, causes grogginess.
This calculator adds 15 minutes to account for the time it takes to fall asleep, then calculates wake/sleep times based on complete 90-minute cycles.
For most adults, 5-6 complete cycles (7.5 to 9 hours) is ideal. However, individual needs vary. Experiment to find what works best for you.