How long is a sleep cycle?

A typical sleep cycle lasts about 90 minutes and goes through 4 stages: light sleep, deep sleep, and REM sleep. Waking up at the end of a cycle (rather than in the middle) helps you feel more refreshed.

How many hours of sleep do adults need?

Most adults need 7–9 hours of sleep per night. Teenagers need 8–10 hours, and school-age children need 9–11 hours. Individual needs vary, and some people function well on slightly more or less.

What is the best time to wake up?

The best wake time depends on your bedtime and sleep cycles. This calculator helps you find times that align with natural cycle endings, typically in multiples of 90 minutes after falling asleep (allow ~15 min to fall asleep).

Sleep Calculator

Find the ideal bedtime or wake-up time based on your sleep cycles. Wake up at the right moment to feel alert and refreshed.

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