Sleep Cycle Calculator

Calculate optimal bedtime and wake up time based on sleep cycles to help you get better quality sleep.

Calculate Bedtime

What time do you want to wake up?

Hour

Minute

Calculate Wake Up Time

What time do you want to go to sleep?

Hour

Minute

If you want to go to sleep now

What is a Sleep Cycle?

A sleep cycle is the natural pattern of sleep your body goes through during the night. One complete sleep cycle lasts approximately 90 minutes and includes stages of light sleep, deep sleep, and REM (Rapid Eye Movement) sleep.

The average human takes 15 minutes to fall asleep
One complete sleep cycle lasts approximately 90 minutes
A good night's sleep consists of 5-6 complete sleep cycles
Waking up at the end of a sleep cycle will make you feel more refreshed

How to Use the Sleep Calculator

Our sleep calculator works by calculating optimal bedtime and wake-up times based on 90-minute sleep cycles and 15 minutes to fall asleep.

Choose what time you want to wake up and the calculator will tell you the best times to go to sleep
Or choose what time you want to go to sleep and the calculator will suggest the best times to wake up
You can also click "go to sleep now" to calculate the best wake-up times if you fall asleep right away
Try to wake up at the end of a complete sleep cycle - you'll feel more refreshed and alert

Frequently Asked Questions

Why are sleep cycles important?

Sleep cycles are important because waking up at the end of a cycle (rather than in the middle of deep sleep) helps you feel more alert and refreshed. Being awakened during deep sleep can cause sleep inertia, making you feel groggy and disoriented.

Is everyone's sleep cycle exactly 90 minutes?

While 90 minutes is the average, individual sleep cycles can vary between 80 to 120 minutes. Our calculator uses the 90-minute standard which works effectively for most people.

How many sleep cycles do I need?

Most adults need 5-6 complete sleep cycles per night (7.5-9 hours of sleep). Teenagers may need more, while older adults may need slightly less.

What if I can't go to sleep at the recommended times?

If you can't go to sleep at the exact recommended times, try to choose the time closest to a complete sleep cycle. Even partial adjustments can improve your sleep quality.

Does this calculator account for the time it takes to fall asleep?

Yes, our calculator automatically adjusts for the 15 minutes it takes most people to fall asleep. This means if you go to bed at the suggested time, you should enter the sleep cycle at the right moment.

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