Sleep Calculator
Find out exactly what time to go to sleep or wake up based on 90-minute sleep cycles. Instantly calculates your optimal sleep schedule for waking up refreshed. 100% free with no app required.
About Sleep Cycles
Human sleep alternates between light and deep sleep in approximately 90-minute cycles. Waking up during cycle transitions helps you feel more refreshed.
Sleep quality depends not only on duration but also on depth and continuity.
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FAQ
Q1
What are sleep cycles?
Human sleep alternates between REM (light sleep) and non-REM (deep sleep) in approximately 90-minute cycles. Waking up during cycle transitions helps you feel refreshed.
Q2
Is there an ideal bedtime?
Generally, bedtime between 10-11 PM is considered ideal. It's important to enter deep sleep during 10 PM-2 AM when growth hormone secretion is most active.
Q3
Should naps be included in total sleep time?
Naps complement nighttime sleep, but excessive napping can affect nighttime sleep. Short naps of 15-30 minutes are recommended.
Q4
Is catching up on sleep during weekends effective?
Excessive weekend sleep can disrupt your body clock and make Monday mornings difficult. Keep the difference within 2 hours from weekdays.
Q5
Does required sleep time decrease with age?
Yes, generally required sleep time decreases with age, and sleep tends to become lighter. 7-8 hours is appropriate for older adults.
Tips for Quality Sleep
- • Go to bed and wake up at the same time every day (including weekends)
- • Avoid smartphones and computers 1-2 hours before bedtime
- • Keep bedroom cool (61-66°F), dark, and quiet
- • Avoid caffeine after 2 PM
- • Avoid intense exercise or large meals before bedtime
- • Get moderate exercise and sunlight exposure during the day
This information is general guidance. Consult doctors, sleep specialists, or medical institutions for detailed advice.