Sleep Cycle Calculator

Functions as a bedtime and wake up tool in order to facilitate sleeping hours tracking.

There is more on how to use the tool for bedtime and wake up calculations and on national sleep guidelines, in the text below.

As a dual sleep tool, the sleep cycle calculator helps with waking up at a certain hour or with deciding at what time to go to bed in order to get the desired amount of sleep and still wake up in time.

It is flexible and performs the calculation as soon as all three fields are completed.

It is important to discover the average time to fall asleep but this is often difficult, especially without help.

Average falling asleep is between 7 and 14 minutes but can vary due to emotional, environmental or health factors.

Desired time to sleep should in theory respect health guidelines and should be enough as per individual requirements as not to create any sleep debt.

Desired wake up time: *
Average time to fall asleep:
Desired time to sleep:
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Bedtime: *
Average time to fall asleep:
Desired time to sleep:

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Steps on how to print your input & results:

1. Fill in the calculator/tool with your values and/or your answer choices and press Calculate.

2. Then you can click on the Print button to open a PDF in a separate window with the inputs and results. You can further save the PDF or print it.

Please note that once you have closed the PDF you need to click on the Calculate button before you try opening it again, otherwise the input and/or results may not appear in the pdf.

Sleeping hours, whether we are talking about the actual time spent sleeping or the bedtime and wake up times, are an important component of sleep related life choices and can influence in great proportion sleep quality, level of rest or tiredness during the day and the occurrence of sleep disorders.

There are two different tabs in the sleep cycle calculator, each with a designated purpose. How they work will be explained separately below.


The bedtime calculation

Helps determine when is the right time to go to sleep if you want to wake up at a certain hour and want to sleep a certain amount of time.

The first field, the desired wake up time is mandatory and requires an hour and minute input and also the selection of either AM or PM.

The second field, the average time to fall asleep field is option, thus can be left blank if the user doesn’t want to customize it. In this case, an average value of 15 minutes will be used in the calculation.

The third field is also optional and in case the user does not fill it in, an average of 8 hours of sleep will be used.


The wake up calculation

This tab computes the time to wake up given the bedtime and time to sleep.

Not only the bedtime field is flexible, thus the user being able to customize it in terms of hour and minutes, but the tab also benefits from an average time to fall asleep to add to the preciseness of the calculation. If left uncompleted, an average time to fall asleep of 15 minutes will be assumed.

The last field is the desired time to sleep, that can be input in hours, and if left uncompleted, will be considered by default as 8 hours.


How much sleep is enough?

The National Sleep Foundation has published guidelines that are customized per age group, as presented in the below table:

Age Sleep Needs
Newborns (0 - 2 months) 12 - 18 hours
Infants (3 - 11 months) 14 - 15 hours
Toddlers (1 - 3 years) 12 - 14 hours
Preschoolers (3 - 5 years) 11 - 13 hours
School-age children (5 - 10 years) 10 - 11 hours
Teens (10 - 17 years) 8.5 - 9.25 hours
Adults (18 years or more) 7 - 9 hours

The average time that it takes to fall asleep is between 7 and 14 minutes and will vary widely, depending on emotional, environment or health factors.

Times below the average are usually indicative of sleep deprivation or sleep debt.

There is also a gender gap when it comes to sleep time, with women said to require and extra hour of sleep than men.

Sleeping for less than 5 hours in 24 hours, thus 17 hours of wakefulness, leads to a decrease in performance similar to that of a blood alcohol level of 0.05%.



1. Hirshkowitz M, Whiton K et al. National Sleep Foundation’s sleep time duration recommendations: methodology and results summary. Sleep Health: Journal of the National Sleep Foundation. 2015.

2. Fuller PM, Gooley JJ, Saper CB. Neurobiology of the sleep-wake cycle: sleep architecture, circadian regulation, and regulatory feedback. J Biol Rhythms. 2006; 21(6):482-93.

3. Saper CB, Scammell TE, Lu J. Hypothalamic regulation of sleep and circadian rhythms. Nature. 2005; 437(7063):1257-63.

Specialty: Sleep Medicine

System: Nervous

Type: Calculator

No. Of Variables: 3

Article By: Denise Nedea

Published On: March 15, 2017

Last Checked: March 15, 2017

Next Review: March 9, 2023