Calculate optimal bedtimes and wake times based on 90-minute sleep cycles for better mornings.
Sleep Duration
8h 0m
Full Cycles
good
Each sleep cycle lasts ~90 minutes. Waking at the end of a cycle leaves you feeling refreshed. Aim for 5-6 complete cycles per night.
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.
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.
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.