We're here to help you sleep better
A sleep cycle is approximately 90 minutes long and includes different stages: light sleep, deep sleep, and REM (rapid eye movement) sleep. Most people go through 4-6 cycles per night.
Waking up during deep sleep can leave you feeling groggy and disoriented (called "sleep inertia"). By timing your wake-up to occur between cycles, you wake during light sleep and feel more refreshed.
Sleep cycles vary slightly between individuals (85-100 minutes), and the time to fall asleep differs too. Our calculator uses the average 90-minute cycle and lets you adjust your fall-asleep time for better accuracy.
Research suggests adults need 7-9 hours of sleep for optimal health. 5 cycles (7.5 hours) and 6 cycles (9 hours) fall within this recommended range.
Our ambient sounds stream from our CDN and loop in the app. You can download the sound library from the Ambient Sounds menu so your sounds keep working offline. The sleep timer will automatically stop the sound after your chosen duration.
Yes! On iOS, notifications are scheduled through the system and will appear even if the app isn't running. Make sure notifications are enabled in your device settings.
When you first use the app, you'll be asked to allow notifications. If you declined, you can enable them in Settings > Sleep Cycles > Notifications.
Absolutely. Sleep Cycles doesn't collect any personal data. All your preferences are stored locally on your device. See our Privacy Policy for details.