Sleep Cycle Calculator

Sleep Cycle Calculator works out the best times to fall asleep or wake up so your alarm does not interrupt deep sleep. Choose a wake-up time and the app lists several bedtimes spaced by full ninety-minute sleep cycles, or choose a bedtime and see the wake times that complete four, five, or six cycles.

Key features
• Bidirectional planner: find bedtime from wake time, or wake time from bedtime
• Adjustable fall-asleep buffer for the minutes it takes you to drift off
• Tunable cycle length when yours runs shorter or longer than average
• Age-group highlights for adults, teens, and children
• Quick-start presets for common alarms, bedtimes, and power naps
• Saved plans with notes and a shareable summary
• Modern edge-to-edge design optimized for all devices

Each suggestion shows how many cycles and total hours of sleep it delivers, with the recommended window highlighted for the age group you pick.