Recommended
21:15
6 cycles • 9h 15m
Sleep cycle calculator
Sleep Time
Find sleep or wake times aligned with 90-minute sleep cycles.
Wake-up time
Time to fall asleep
15 min
Try going to sleep at:
Recommended
22:45
5 cycles • 7h 45m
Optional
00:15
4 cycles • 6h 15m
Optional
01:45
3 cycles • 4h 45m
Sleep time questions
What is a 90-minute sleep cycle?
A sleep cycle commonly lasts about 90 minutes and includes several sleep stages. Waking near the end of a cycle often feels lighter than waking in the middle of one.
How many hours of sleep do adults need?
Many adults need around 7 to 9 hours of sleep per night. Individual needs can vary based on age, activity, health, and sleep habits.
When should I sleep if I want to wake up at a certain time?
Start from your target wake-up time, then count back 4 to 6 sleep cycles. Include your estimated time to fall asleep so the plan is more realistic.
Does this calculator replace medical advice?
No. This calculator provides general estimates only and is not a diagnosis or medical advice. Consult a qualified health professional if you have recurring sleep problems.