Health Tools

수면 주기 계산기

90분 수면 주기를 기반으로 일어나거나 잠들기에 가장 좋은 시간 찾기

Best bedtimes to wake up at 07:00 AM

09:46 PM

6 sleep cycles(9 hours of sleep)Optimal

11:16 PM

5 sleep cycles(7.5 hours of sleep)Recommended

12:46 AM

4 sleep cycles(6 hours of sleep)

02:16 AM

3 sleep cycles(4.5 hours of sleep)

03:46 AM

2 sleep cycles(3 hours of sleep)

05:16 AM

1 sleep cycle(1.5 hours of sleep)

A full sleep cycle lasts about 90 minutes and includes light sleep, deep sleep, and REM stages. Waking up at the end of a cycle (instead of mid-cycle) helps you feel more refreshed. Most adults need 4–6 complete cycles per night.

Sleep Calculator — Wake Up Refreshed

Find the ideal bedtime or wake-up time based on 90-minute sleep cycles. Waking up at the end of a cycle (rather than mid-cycle) leaves you feeling more rested.

FAQ

What is a sleep cycle?

A sleep cycle is approximately 90 minutes long and includes light sleep, deep sleep (NREM), and REM sleep. Most adults complete 4–6 cycles per night.

How much sleep do I need?

Adults: 7–9 hours (4–6 cycles). Teenagers: 8–10 hours. School-age children: 9–11 hours. These are guidelines — individual needs vary.

Why do I feel tired even after 8 hours?

You may be waking up in the middle of a deep sleep cycle. Try adjusting your alarm to the nearest 90-minute boundary, or use a sleep tracking app.

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