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๐ŸŒ™

Sleep Calculator

When should you sleep to wake up refreshed?

Waking up at the end of a sleep cycle (~90 min) helps you feel more refreshed. Find your optimal bedtime or wake time now!

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๐Ÿง  What is a Sleep Cycle?

Sleep consists of 4 stages (N1, N2, N3, REM) that repeat in cycles. Each cycle is about 90 minutes, and completing 4-6 cycles per night is ideal.

๐Ÿ’คN1 (Drowsy)1-7 min
โ†’
๐Ÿ˜ดN2 (Light Sleep)~50%
โ†’
๐Ÿ›ŒN3 (Deep Sleep)~20%
โ†’
๐ŸŒˆREM (Dream Sleep)~25%
โ†ป This cycle repeats throughout the night (usually 4-6 times)
๐Ÿ’คN1 (Drowsy)

The transition to sleep. Light sleep where you can easily wake up.

๐Ÿ˜ดN2 (Light Sleep)

Heart rate slows and body temperature drops. Memory consolidation begins.

๐Ÿ›ŒN3 (Deep Sleep)

The most restorative stage. Body repair and immune system strengthening occur.

๐ŸŒˆREM (Dream Sleep)

Brain is active and dreams occur. Important for memory and emotional processing.

๐Ÿ’ก Key Point: Waking up at the end of a sleep cycle (especially after REM) helps you feel more refreshed. This is why a sleep calculator can help!

๐Ÿ“Š Recommended Sleep by Age

Sleep recommendations based on CDC and sleep research guidelines.

Age GroupRecommended Sleep
Newborn (0-3 months)14-17 hours
Infant (4-12 months)12-16 hours
Toddler (1-2 years)11-14 hours
Preschool (3-5 years)10-13 hours
School Age (6-12 years)9-12 hours
Teen (13-18 years)8-10 hours
Adult (18-60 years)7+ hours
61-64 years7-9 hours
65+ years7-8 hours

* These recommendations are for 24 hours. Nap time is included for infants and young children.

๐Ÿ’ก Tips for Better Sleep

Simple but effective ways to improve your sleep quality.

โฐ

Keep a Consistent Schedule

Going to bed and waking up at the same time every day stabilizes your circadian rhythm.

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Watch Caffeine Intake

Avoid coffee, tea, and other caffeinated drinks at least 6 hours before bed.

๐Ÿ“ฑ

Reduce Screen Time

Limiting phone and computer use 1 hour before bed helps melatonin production.

๐ŸŒ™

Create a Sleep Environment

A dark, cool, and quiet room promotes deeper sleep.

๐Ÿ›’ Recommended Items for Better Sleep

Products that can help improve your sleep quality.

๐Ÿ›๏ธ Ergonomic Pillow๐ŸŒ‘ Blackout Curtains๐ŸŽง White Noise Machine๐Ÿ’Š Sleep Supplements

Tool guide

Sleep Calculator

Calculate optimal sleep time

Calculate optimal bedtime/wake time based on sleep cycles.

Estimate bedtime or wake-up time from sleep cycles

Choose a wake-up time or bedtime, adjust sleep latency, then copy the sleep-cycle options or share a stable calculator link.

  • Calculate bedtime options from a target wake-up time
  • Calculate wake-up options from a planned bedtime
  • Use sleep latency so shared results match how long it takes to fall asleep

Related tools

Age CalculatorTime CalculatorTimer

Add wind-down time to bedtime planning

The suggested bedtime is the start of the sleep window, not the start of your routine. Add a realistic buffer if you need time to get ready for bed.

  • Include time for screens off, hygiene, reading, or commute preparation before the sleep window starts
  • Adjust sleep latency when it usually takes more than a few minutes to fall asleep
  • Use Timer or Alarm Clock for the routine steps before the calculated bedtime

A practical sleep-cycle estimate

ClockHub uses a common 90-minute sleep-cycle estimate and visible age-based sleep-duration guidance. Treat the result as general planning help, not medical advice or a guarantee of sleep quality.