Sleep Calculator
Wake up refreshed by timing your sleep to complete 90-minute cycles.
Based on 90-min sleep cycles + ~14 min to fall asleep.
Go to bed at one of these times to wake at 07:00 feeling refreshed:
09:46 PM
Excellent (9h)
6 cycles
9h sleep
11:16 PM
Great (7.5h)
5 cycles
7h 30min sleep
Recommended12:46 AM
Good (6h)
4 cycles
6h sleep
02:16 AM
Minimum (4.5h)
3 cycles
4h 30min sleep
Sleep & Muscle Recovery
- 🧬 Growth hormone peaks during deep sleep (cycles 1–2). Never skip these.
- 🔧 Muscle repair primarily happens in cycles 3–5 (REM + slow-wave sleep).
- 📉 Less than 6h increases cortisol, reduces testosterone, and impairs protein synthesis.
- 📵 No screens 30–60 min before bed — blue light suppresses melatonin by up to 50%.
- 🌡️ Cool room (16–19°C) significantly improves sleep quality.