Here is the direct link for: Bedtime Calculator.
Every wonder why some mornings you feel so rested and others like you got up on the wrong side of the bed?
This idea of a bedtime calculator is a cool idea. The premise is that our nightly sleep time consists of several 1-1/2 hour cycles and depending on when you fall asleep and eventually wake up within these cycles can determine whether you will awake feeling rested or not.
The site (unclear the actual source) says that "it takes the average human fourteen minutes to fall asleep" and "a good night's sleep consists of 5-6 complete sleep cycles. Each sleep cycle lasts about 90 minutes". So if you were to wake up in mid-cycle then you would feel more tired and groggy, but waking up at the end or beginning of a fresh cycle will leave you more alert and refreshed.
The link is a calculator that allows you to type in either your bedtime OR desired wake time. The calculator then gives you the times to wake up OR the times to actually go to bed. For instance, if you were to fall asleep tonight around 10:00 P.M., then the best times to wake up are: 11:30 P.M. or 4:00 A.M. or 5:30 A.M. or 7:00 A.M. Remember that it takes an average of 14 minutes to fall asleep!
I use this calculator on a weekly basis. I have an ongoing commitment in which I need to get up at 1:30 A.M. on Friday mornings. And when I plan accordingly, I wake up more refreshed even after only being asleep for 3 or so hours!
The red pin award for great resource that is helpful!