Find the best time to go to sleep or wake up, based on 90-minute sleep cycles.
Based on 90-minute sleep cycles plus about 15 minutes to fall asleep.
Choose whether you want to wake up at a set time or go to sleep right now, and see several suggested times that align with complete 90-minute sleep cycles — waking up between cycles, rather than in the middle of one, tends to feel less groggy.
A full sleep cycle — moving through light sleep, deep sleep and REM sleep — takes about 90 minutes on average; waking up at the end of a cycle rather than partway through it tends to feel more refreshing.
No — this is a general rule-of-thumb tool based on typical averages. Individual sleep cycles vary, and persistent sleep problems are worth discussing with a healthcare provider.
No — actual sleep cycle length varies roughly between 70 and 120 minutes depending on the person, and even night to night, so treat these times as a helpful starting point, not an exact science.