Sleep Calculator: When to Go to Bed or Wake Up

Pick the time you need to wake up, or the time you are going to bed. The calculator adds about 15 minutes to fall asleep and counts in sleep cycles of roughly 90 minutes.

Cycle length varies between people and through the night (about 70 to 120 minutes), so treat these times as a starting point. Adults need at least 7 hours on a regular basis; people in hard training often do better with 8 or more. See how much sleep do I need.