Question 1

What time should I wake up to feel refreshed?

Accepted Answer

You should wake up at the end of a sleep cycle to feel most refreshed. Sleep cycles last about 90 minutes. Use our sleep calculator: enter your bedtime and it will show you the ideal wake-up times based on 4, 5, or 6 complete sleep cycles.

Question 2

What time should I go to sleep?

Accepted Answer

Enter your desired wake-up time in our sleep calculator, and it will calculate the best bedtimes based on 90-minute sleep cycles. For 8 hours of sleep (5-6 cycles), it takes about 15 minutes to fall asleep, so plan accordingly.

Question 3

How long is a sleep cycle?

Accepted Answer

A complete sleep cycle lasts approximately 90 minutes and includes light sleep, deep sleep (slow-wave sleep), and REM sleep. Most adults need 4-6 complete sleep cycles per night, which equals 6-9 hours of sleep.

Question 4

Why do I feel groggy even after 8 hours of sleep?

Accepted Answer

You may be waking up in the middle of a sleep cycle, which causes sleep inertia (grogginess). Try waking up at the end of a complete 90-minute cycle instead. Our sleep cycle calculator helps you find the perfect wake-up time.

Question 5

How many sleep cycles do I need per night?

Accepted Answer

Most adults need 5-6 complete sleep cycles per night, which equals 7.5-9 hours of sleep. Younger adults and teenagers may need 6+ cycles. Our calculator recommends the optimal number of cycles based on your schedule.

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