Sleep Calculator

How to Use

1. Select calculation mode: "Bedtime" or "Wake-up time".
2. Enter the corresponding time based on your choice.
3. Click the "Calculate Best Times" button to see the recommended list.
4. Arrange your schedule according to the recommendations to improve sleep quality.

Calculation Principle

Human sleep consists of several sleep cycles, each about 90 minutes, including:

• Light Sleep (N1/N2): Body relaxes, brain activity slows.
• Deep Sleep (N3): Body repairs, immunity strengthens.
• REM: Dreaming stage, helps memory and emotion regulation.

Research shows waking up at the end of a complete sleep cycle makes you feel more refreshed and avoids being woken from deep sleep.
Sleep quality is more important than just sleep duration.

This calculator works by:

1. You enter your desired wake-up or bedtime.
2. Assumes an average 15 minutes to fall asleep (not counted in cycles).
3. Calculates 4~7 complete cycles before/after the reference time.
4. These times are the best recommended bed/wake times for better sleep quality.

Following these recommendations can reduce grogginess and improve daytime energy and focus.