Sleep Calculator

This sleep calculator will help you find the best bedtime for you, by maximizing your full sleep cycles. Sleep consists of 90-minutes-long sequences, repeated throughout the night. You'll wake up feeling better if you wake up at the end of a cycle, rather than in the middle of it, so use this calculator to find out what time you should go to sleep if you want to wake up refreshed and alert. And if you are still wondering how important it is to get the right amount of sleep, check how deadly your current sleeping routine is!

If you're interested in how much sleep we need at different ages, whether 6 hours of sleep is enough, what our natural sleep pattern is and what are good sleep habits - keep scrolling and you'll find the answer.

What time should I go to sleep?


To wake up at : you should go to bed at:

6 cycles, 9h of sleep

Recommended for long-sleepers
5 cycles, 7h30m of sleep

Recommended for average-sleepers
4 cycles, 6h of sleep

Recommended for short-sleepers
3 cycles, 4h30m of sleep

2 cycles, 3h of sleep

1 cycle, 1h30m of sleep

What are sleep cycles and stages of sleep?

While sleeping, our brains go through several sleep cycles. An average person needs 5-6 cycles to feel fully regenerated in the morning. One sleep cycle lasts around 90 minutes and consists of 5 stages: the first four stages are non-REM stages, where stage 1 and 2 are known as light sleep stages, stage 3 (and 4 in the previous definition) are deep sleep stages, and the last one is REM (rapid eye movement) sleep.

The duration of each stage oscillates between 5 and 15 minutes. Early in the night, stages of deep sleep are longer than REM sleep, but this swaps round as the night progresses. People's brains usually don't go from stages 1 to 5, but rather: stages of light sleep, stages of deep sleep, REM, and then back to stages of light sleep and stages of deep sleep.

Light sleep stages (N1, N2) are characterized by muscle contractions and being woke easily. Your body is preparing, slowly, for deep sleep, with your brain waves becoming slower.

Deep sleep stages (N3, previously divided into N3 and N4) are also known as delta sleep or slow wave sleep. It's very hard to wake someone during this stage. It's also the most important sleep stage as it refreshes you the most and reduces your need for sleep. That's why if you nap for too long during the day (entering deep sleep) you don't feel as sleepy that night. Also, during this stage, your body and muscles are being restored by growth hormones.

REM sleep stage (R) is where dreams happen. Your brain imitates waves just as if you were awake, with your eyes moving rapidly but still closed.

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