Sleep Calculator
Sleep calculator helps you wake up feeling refreshed by timing your sleep cycles. Based on the average 90-minute sleep cycle, this tool calculates the optimal times to fall asleep or wake up. Wake between cycles, not during them, for better rest and more energy throughout your day.
Calculate your ideal bedtime or wake-up time based on 90-minute sleep cycles. All calculations happen in your browser.
Average is 10-20 minutes
💤 If you go to bed at...
💡 Tip:
These times let you wake up at the end of a sleep cycle. You'll feel more refreshed waking between cycles than in the middle of one.
Frequently Asked Questions
- How does the sleep calculator work?
- The calculator is based on the average 90-minute sleep cycle. Waking up at the end of a cycle (rather than during deep sleep) helps you feel more refreshed and alert.
- How many hours of sleep do I need?
- Most adults need 7-9 hours (5-6 complete sleep cycles). The quality of sleep and waking between cycles matters as much as total duration.
- Why 90 minutes per cycle?
- A typical sleep cycle lasts about 90 minutes and includes light sleep, deep sleep, and REM sleep. Completing full cycles helps you wake up naturally and feel better.
- What if I can't fall asleep in 14 minutes?
- You can adjust the "fall asleep time" setting. Some people need 5 minutes, others need 30. Experiment to find what works for you.
- Should I wake up after exactly 6 cycles?
- Not necessarily. While 6 cycles (9 hours) is ideal, 5 cycles (7.5 hours) works well for many adults. Listen to your body and choose what makes you feel most rested.