How it works
Sleep Quality Calculator - Track Sleep Debt & Bedtime
Calculate optimal bedtime or wake time based on 90-minute sleep cycles. Waking at the end of a cycle (not mid-cycle) helps you feel more refreshed.
Track sleep quality, duration, and score. Calculate sleep debt and view stage breakdown (Light, Deep, REM).
Read full guide & technical breakdown
Most adults need 7–9 hours (5–6 cycles). Caffeine has a 5–6 hour half-life — avoid it near bedtime.