CCalcBOX
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Sleep Calculator

Find optimal bedtime and wake-up time using sleep cycles.

⏰ Wake-Up Time

:

🌙 Recommended Bedtime

To wake at 07:00... (includes ~14 min to fall asleep)

21:46
6 cycles（9hours）
⭐⭐⭐⭐
Plenty of sleep
LightDeepREM
23:16
5 cycles（7.5hours）
⭐⭐⭐⭐⭐
Optimal for most ⭐Recommended
LightDeepREM
00:46
4 cycles（6hours）
⭐⭐⭐
Less but functional
LightDeepREM
02:16
3 cycles（4.5hours）
⭐
Minimum (short sleep)
LightDeepREM

📋 Recommended Sleep by Age

Newborn (0-3 mo)14-17 hours
Infant (4-11 mo)12-15 hours
Toddler (1-2 yr)11-14 hours
Preschool (3-5 yr)10-13 hours
School Age (6-13 yr)9-11 hours
Teen (14-17 yr)8-10 hours
Adult (18-64 yr)7-9 hours
Senior (65+ yr)7-8 hours

💡 Tips for Better Sleep

🌡️Keep bedroom at 18-22°C
📱Avoid screens 1 hour before bed
☕No caffeine after 2 PM
🛁Bathe 90 minutes before bed
🌅Wake at the same time daily
🏃Exercise regularly (not within 3 hours of bed)

About Sleep Calculator

A tool that calculates optimal bedtime and wake-up times based on 90-minute sleep cycles.

Waking at the end of a sleep cycle helps you feel refreshed. Time to fall asleep (~14 min) is included in calculations.

📖How to Use
  1. 1Enter your wake-up time or bedtime
  2. 2See recommended sleep or wake times based on 90-minute sleep cycles
  3. 3Plan your sleep schedule to wake up feeling refreshed
💡Tips & Knowledge
  • •Sleep runs in 90-minute cycles. Aim for 4–6 cycles (6–9 hours) for optimal rest
  • •It takes an average of 14 minutes to fall asleep. Get into bed 14 minutes before your target sleep time
  • •Blue light suppresses melatonin production. Avoid screens for at least 1 hour before bed

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All calculations run in your browser. No data is sent to any server.