Sleep Cycle Calculator
Find the perfect time to wake up or go to bed.
Calculate Your Sleep
How This Calculator Works
How to Use the Sleep Calculator
1. Choose Your Goal: Select either "I want to wake up at..." or "I want to go to bed at...".
2. Set the Time: Use the time picker to set your desired wake-up or bedtime.
3. View Results: The calculator instantly shows you the best times. These times are based on 90-minute sleep cycles.
The calculations automatically include the **15 minutes** it takes the average person to fall asleep.
What is a Sleep Cycle?
Your sleep isn't one long, unchanging state. Instead, you cycle through different stages of sleep: Light Sleep, Deep Sleep, and REM (Rapid Eye Movement) sleep.
One full cycle through these stages takes an average of **90 minutes**.
The key to waking up refreshed is to wake up at the **end** of a cycle, not in the middle of it. Waking up during a deep sleep phase is what causes "sleep inertia"—that groggy, confused, and heavy feeling that can last for an hour or more.
Recommended Sleep
While one or two cycles might work for a quick nap, a healthy night of sleep consists of multiple full cycles.
| Sleep Cycles | Total Sleep Time | Recommendation |
|---|---|---|
| 6 Cycles | 9 hours | Ideal |
| 5 Cycles | 7.5 hours | Recommended |
| 4 Cycles | 6 hours | Minimum |
| 3 Cycles | 4.5 hours | Not Recommended |