Sleep Calculator: When to Go to Sleep Based on Science
Deciding when to go to sleep should be based on your fixed morning wake-up commitment. Subtracting 5 complete 90-minute cycles (7.5 hours) plus a 15-minute sleep latency buffer ensures you fall asleep during your biological circadian dip and awaken during light sleep.
How to Determine When to Go to Sleep
Your ideal bedtime aligns when homeostatic sleep pressure (adenosine accumulation) and circadian melatonin peaks coincide. For deeper context, see our related guides on wake-up time schedule and nighttime bedtime routine guide.
Target Bedtime Options by Wake Time
Reference this bedtime guide:
| Desired Wake Time | Optimal Bedtime (5 Cycles) | Secondary Bedtime (4 Cycles) |
|---|---|---|
| 5:45 AM | 10:00 PM | 11:30 PM |
| 6:15 AM | 10:30 PM | 12:00 AM |
| 6:45 AM | 11:00 PM | 12:30 AM |
| 7:15 AM | 11:30 PM | 1:00 AM |
The 3-2-1 Wind-Down Protocol
Stop heavy meals 3 hours before bed; stop liquid intake 2 hours before bed; stop screens and artificial light 1 hour before bed.
Calculate Your Personalized Sleep Schedule
Eliminate guesswork. Use our free, evidence-based sleep calculators to synchronize your alarms with your biology.
Related Bedtime Science Guides
Deepen your circadian science and sleep scheduling knowledge with these companion guides:
Frequently Asked Questions
What happens if I miss my calculated bedtime window?
If you miss your optimal bedtime by 45 minutes, wait another 45 minutes to align with the next 90-minute cycle rather than sleeping mid-cycle.
Our editorial research team specializes in sleep chronobiology and circadian rhythm science, translating peer-reviewed polysomnography protocols into accessible digital tools. All sleep models are verified against American Academy of Sleep Medicine (AASM) standards.