Sleep Calculator
Choose your wake time or planned bedtime and get suggested cycle-based sleep times.
Quick use
- Select wake-time mode or bedtime mode.
- Choose your target time.
- Use one suggested timing for a 7-night test.
What is a sleep cycle? (Simple meaning)
Your sleep goes in rounds. One round is called one cycle.
One cycle is about 90 minutes (1 hour 30 minutes).
In this tool: 4 cycles is about 6 hours, 5 cycles is about 7 hours 30 minutes, 6 cycles is about 9 hours.
Suggested times
- • Fall asleep around 9:46 PM (6 cycles, about 9h)
- • Fall asleep around 11:16 PM (5 cycles, about 7h 30m)
- • Fall asleep around 12:46 AM (4 cycles, about 6h)
Which option should I pick?
4 cycles (about 6 hours)
Good: easier on very busy days.
Not good: often not enough sleep if used daily.
5 cycles (about 7 hours 30 minutes)
Good: best balance for most people.
Not good: can still feel less if your sleep breaks often at night.
6 cycles (about 9 hours)
Good: best for recovery when very tired.
Not good: may be hard to follow every day.
Start with 5 cycles for 7 nights. Then change only if your morning energy is still poor.
This is a planning tool, not medical advice. It assumes ~90-minute sleep cycles and ~14 minutes to fall asleep.
Related categories and guides
Continue with these pages if you want to understand sleep timing better and build a practical night routine.