Sleep Calculator: Wake Up Fully Rested and Energized

Updated in October 2023

You can use a sleep calculator to calculate how many 90-minute cycles you need in order to wake up when the last cycle ends. This can help you to wake up more relaxed, energized and in a good mood. 

See what time you should wake up at or go to bed at to get a good night's sleep using the calculator below:

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What is a sleep cycle?

The sleep cycle is characterized by a set of sleep stages that begin when a person falls asleep and last until the REM sleep stage. REM is the deepest sleep stage and guarantees the most restorative and relaxing sleep. This sleep stage is the most difficult to reach for many people.

The body goes through several cycles lasting between 90 and 100 minutes per cycle and normally 4 to 5 cycles are needed per night, which corresponds to 8 hours of sleep.

What are the stages of sleep?

There are 4 stages of sleep:

  • Light sleep - stage 1, which is a very light stage and lasts about 10 minutes. This phase starts the moment you close your eyes, but you can easily wake up at any sound.
  • Light sleep - stage 2, which lasts about 20 minutes and in this stage the body is already relaxed, but the mind is still active, so it is still possible to wake up during this stage of sleep.
  • Deep sleep - stage 3, in which the muscles are completely relaxed and the body is less sensitive to noises or movements, making it more difficult to wake up. This stage is very important for the body's recovery.
  • REM sleep - stage 4, also known as the deep sleep stage, is the last stage of the sleep cycle and lasts about 10 minutes, starting 90 minutes after falling asleep.

In the REM phase, the eyes move very quickly, the heartbeat increases and dreams appear. REM sleep is difficult to achieve, which is why it's important to dim the lights in the room and not use your cell phone or computer before going to sleep, as this makes it easier to reach REM sleep. 

Why do we need good sleep?

Sleeping well is essential for the body to function properly, because it is when the body is able to recover its energy and regulate  hormones levels that are needed to optimal functioning and metabolism. During sleep, the mind is able to consolidate information obtained throughout the day, and the body is able to repair tissues and strengthen the immune system.

Therefore, when you don't get a good night's sleep, you may experience consequences such as mood swings, increased inflammation in the body, lack of energy and a weakened immune system. Reduced sleep and sleep quality can also increase your risk for developing certain diseases, such as obesity, diabetes and high blood pressure.