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🌙 When to Go to Sleep Calculator - Perfect Bedtime & Wake Up Time

Calculate the perfect bedtime and wake-up times based on 90-minute sleep cycles. Get better quality sleep and wake up refreshed naturally!

Set Your Wake Up Time

Enter the time you want to wake up to calculate the best bedtime

Set Your Sleep Time

Enter the time you want to go to sleep to calculate the best wake-up times

Sleep Cycle Science

90-Minute Cycles

A complete sleep cycle lasts about 90 minutes, including light sleep, deep sleep, and REM sleep

5-6 Cycles

Adults need 5-6 sleep cycles per night, approximately 7.5-9 hours

Natural Awakening

Waking up at the end of a cycle feels more refreshing, avoiding deep sleep interruption

💡 Science-Based Tips for Better Sleep

No Screens 1 Hour Before Bed

Blue light suppresses melatonin production, affecting sleep quality

Keep Room Cool

Ideal sleep temperature is 64-72°F (18-22°C) for faster sleep onset

No Caffeine After 2 PM

Caffeine stays in your system for 6-8 hours, affecting nighttime sleep

No Intense Exercise 3 Hours Before Bed

Exercise raises body temperature and heart rate, requiring cooldown time

No Heavy Meals 2 Hours Before Bed

Digestion requires energy and can disrupt sleep depth

Keep a Consistent Sleep Schedule

Regular bedtimes help regulate your circadian rhythm

❓ Frequently Asked Questions

Why calculate based on 90-minute sleep cycles?

Sleep consists of multiple stages including light sleep, deep sleep, and REM (Rapid Eye Movement) sleep. A complete sleep cycle lasts about 90 minutes. Waking up at the end of a cycle feels more refreshing and alert, avoiding the grogginess that comes from being awakened during deep sleep stages.

Why add 15 minutes for falling asleep?

Most people take 10-20 minutes to fall asleep, so we use an average of 15 minutes. This ensures you enter sleep at the beginning of your planned sleep cycle, rather than lying awake in bed. If you typically fall asleep faster or slower, you can adjust the timing accordingly.

How many hours of sleep do I need per night?

Adults typically need 7-9 hours of sleep, equivalent to 5-6 sleep cycles. Teenagers need 8-10 hours, while older adults may only need 7-8 hours. The key is maintaining a consistent sleep schedule, not just sleep duration. Quality is more important than quantity.

When is the best time to go to sleep?

The optimal bedtime varies by individual, but generally between 10-11 PM is recommended. This aligns with your body's natural circadian rhythm and helps with melatonin production. More importantly, maintain a consistent bedtime to help your body establish a regular rhythm.

How can I improve my sleep quality?

Improve sleep quality by: maintaining regular sleep schedules, creating a comfortable sleep environment (dark, quiet, cool), relaxing before bed (meditation, reading), avoiding caffeine and electronic devices, exercising regularly but not before bedtime. If you have chronic insomnia, consult a doctor.