Free Tool
Sleep Cycle Calculator
Find the best time to go to bed or wake up, based on your sleep cycles.
Adults have ~90 min sleep cycles. Children cycle faster (~60 min), seniors ~80 min.
15 min
Fall asleep instantly
Takes 60 min
How sleep cycles work
A typical sleep cycle lasts about 90 minutes and includes light sleep, deep sleep, and REM sleep. Waking up in the middle of a cycle leaves you feeling groggy.
This calculator works backward from your target wake-up time (or bedtime) to find times that align with the end of a sleep cycle — so you wake up naturally refreshed.