Sleep Cycle Calculator
Wake up refreshed by timing your sleep to complete 90-minute sleep cycles.
It typically takes the average person about 15 minutes to fall asleep.
Recommended Bedtimes
Each option lets you complete full 90-minute sleep cycles, so you wake up between cycles instead of in the middle of one.
Why sleep cycles matter: Sleep happens in cycles of roughly 90 minutes, moving through light sleep, deep sleep, and REM sleep. Waking up in the middle of a cycle (especially deep sleep) can leave you feeling groggy, while waking up between cycles tends to feel more natural. Most adults need 5–6 full cycles (7.5–9 hours) per night.