Sleep Cycle Calculator
Wake up between sleep cycles feeling refreshed
Sleep Analysis
Your sleep duration is reasonable. Try to keep a consistent schedule.
Optimal Bedtimes for 07:00
About Sleep Cycles
A full sleep cycle lasts ~90 minutes. Waking up mid-cycle (during deep sleep) causes sleep inertia — that groggy feeling. By timing your bedtime to complete full cycles before your wake time, you wake up during light sleep feeling refreshed.
Understanding Sleep Cycles
The 90-Minute Rhythm
Sleep cycles through light, deep, and REM stages in ~90 minute intervals. Waking at the end of a cycle (during light sleep) leaves you alert. Waking mid-cycle causes grogginess.
Optimal Duration
Most adults need 5-6 full cycles (7.5-9 hours). The last cycles have longer REM periods, which are crucial for memory consolidation and creative thinking.
Consistency Matters
Going to bed and waking at the same time daily trains your circadian rhythm. Even on weekends, staying within 1 hour of your schedule improves sleep quality.