Sleep Calculator
Find the best time to go to bed or wake up by counting 90-minute sleep cycles — waking at the end of a cycle, when sleep is lightest, beats waking in the middle of one.
Two Ways to Plan
Enter a target wake-up time to get four bedtime options (3 to 6 full cycles), or plan from right now to see the best wake-up times. A configurable fall-asleep buffer (15 minutes by default) keeps the cycle math honest.
Recommended Hours by Age
Every result includes the National Sleep Foundation's recommended sleep ranges, from 14–17 hours for newborns to 7–9 hours for adults.