Sleepyti.me is a web-based sleep calculator that uses average sleep cycle lengths to calculate what time you should go to bed in order to rise at a predetermined well rested and alert.
Plug in the time you need to wake up and hit Calculator. Sleepyti.me charts out the 90 minute sleep cycles that will occur over your sleep period and, working backwards, suggests time you should fall asleep in order to wake up in between those cycles in order to increase alertness and have an easier time peeling yourself out of bed.
For example, let’s say you need to get up at 7:00 AM. It will suggest you fall asleep at 10:00 PM/11:30 PM/1:00 AM/2:30 AM in order to align your sleep cycles with your proposed rising time. Hit up the link below to take it for a spin.