Overview

The Sleep Calculator determines optimal bedtimes or wake-up times based on sleep cycles of approximately 90 minutes each. Each cycle includes NREM and REM stages, and completing 4-6 full cycles per night (6-9 hours) is recommended for restorative sleep.

Formula

Sleep cycle ≈ 90 min | Recommended sleep = cycles × (4-6) = 6-9 hours | Sleep onset latency ≈ 14 min | Bedtime = wake time - (90 min × N) - 14 min | Example: Wake at 7:00 AM → Bedtimes: 9:46 PM, 11:16 PM, 12:46 AM

How to Use

1. 1Enter your desired wake-up time or bedtime.
2. 2Set your average time to fall asleep (default: 14 minutes).
3. 3Click 'Calculate'.
4. 4Review the optimal time candidates aligned with sleep cycles.

Tips

• ✔Waking between sleep cycles feels refreshing; waking mid-cycle causes grogginess.
• ✔Adults need 7-9 hours of sleep per night (National Sleep Foundation recommendation).
• ✔Avoid caffeine and blue light 1-2 hours before bedtime.
• ✔If sleep problems persist, consult a sleep clinic or specialist.

FAQ