Recovery
Sleep Calculator — Best Bedtime for Your Wake-Up Time
Find an ideal bedtime based on your wake-up time and natural 90-minute sleep cycles.
Your Details
The Science of Sleep Cycles
Sleep is not a uniform state. Your brain cycles through distinct stages approximately every 90 minutes. Waking naturally at the end of a cycle — rather than in the middle of deep sleep — is what determines whether you feel refreshed.
Sleep Cycle Stages
- Stage 1 (N1): Light sleep, easily awakened (5 min)
- Stage 2 (N2): Sleep spindles, memory consolidation (20 min)
- Stage 3 (N3): Deep sleep, physical recovery and immune function (30 min)
- REM: Dreaming, emotional processing, cognitive restoration (25 min)
How This Calculator Works
Bedtime = Wake time − (cycles × 90 min) − 14 min (to fall asleep)
How Much Sleep Do You Need?
- Adults (18–64): 7–9 hours (5–6 cycles)
- Teens (14–17): 8–10 hours
- Elderly (65+): 7–8 hours
Pro Tip: Consistency is more important than duration. Going to bed and waking at the same time every day — including weekends — dramatically improves sleep quality.
Tips for Better Sleep Quality
- Avoid screens 1 hour before bed (blue light suppresses melatonin)
- Keep bedroom cool (16–18°C / 60–65°F is optimal)
- Avoid caffeine after 2 PM
- Exercise regularly but not within 2 hours of bedtime