Calculate when the best time to sleep or wake up with this great sleep calculator app.

Simply run the app, and it'll show you the best times to wake up if you sleep now.
There are other options where you could input a time you'd like to sleep, and know when the best times to wake up are.
You can also click on the "Best Time to Wake Up" so it changes to "Best Time to Sleep" and choose when you want to wake up, thus it'd show you the best time to go to bed.
You can even input how long it normally takes you to fall asleep, by selecting the top most counter and setting the minutes you need before falling asleep.