Frequently Asked Questions
Everything you need to know about sleep cycles and our calculator.
A sleep cycle is a progression through different stages of sleep: light sleep (N1 & N2), deep sleep (N3), and REM sleep (dream sleep). Each complete cycle takes approximately 90 minutes.
Research shows that sleep naturally progresses through these stages in approximately 90-minute intervals. This timing allows your brain and body to complete essential restorative processes.
Most people take 10-20 minutes to fall asleep. We use a 15-minute default buffer, but you can adjust this in the calculator based on your personal experience.
Yes! We have a separate nap calculator specifically designed for naps. It helps you time naps to complete either short power naps (20 min) or full sleep cycles (90 min).
Our calculator is based on established sleep science, but it's not medical advice. For sleep disorders or medical conditions, always consult with a healthcare provider.
No. We are privacy-first. All calculations happen in your browser. We don't collect, store, or transmit your sleep times or personal data.
That's often a sign you're waking between cycles! Natural awakenings between cycles typically leave you feeling more refreshed than being awakened mid-cycle.
Frequently Asked Questions
Everything you need to know about sleep cycles and our calculator.
A sleep cycle is the progression through various stages of sleep, typically lasting about 90 minutes. Each cycle includes light sleep, deep sleep, and REM (Rapid Eye Movement) sleep.
Research shows that the average adult completes a full sleep cycle (through all stages) in approximately 90 minutes. This timing helps optimize sleep quality and wakefulness.
Most people take 10-20 minutes to fall asleep. Our calculator includes this buffer time to ensure you wake up after complete cycles.
Yes! For naps, aim for 20-30 minutes (to avoid deep sleep) or 90 minutes (for a complete cycle). Our calculator can help with both.
Absolutely not. We don't use cookies, analytics, tracking pixels, or collect any personal information. All calculations happen entirely in your browser. We have no servers storing your data, no accounts to create, and no way to know when or how you use the tool. Your sleep schedule is completely private.
That's great! Waking up naturally often means you've completed a sleep cycle. If you consistently wake before your alarm, try adjusting your bedtime to match your natural rhythm.