Sleep Calculator
Sleep Calculator - Best Bedtime & Wake-Up Times
The calculator will show you when to go to sleep.
Each sleep cycle is 90 minutes. We add 15 minutes to fall asleep.
Related Calculators
Frequently Asked Questions
Most adults need 5-6 sleep cycles per night. Each cycle lasts about 90 minutes, so 5 cycles = 7.5 hours and 6 cycles = 9 hours of sleep.
Waking mid-cycle causes sleep inertia (grogginess). Waking at the end of a 90-minute cycle means you are in a lighter sleep stage, making it much easier to get up feeling refreshed.
The average person takes about 14 minutes to fall asleep. Our calculator adds 15 minutes to your bedtime to account for this.
The CDC recommends 7-9 hours for adults aged 18-60. Teenagers need 8-10 hours. Children need 9-12 hours. Older adults (65+) should aim for 7-8 hours.