How can I calculate my sleep cycle?

You can estimate sleep cycles by using an average length of around 90 minutes, although actual cycles commonly vary from approximately 80 to 100 minutes. Decide when you need to wake, then count backward in 90-minute blocks. Five estimated cycles equal seven and a half hours, while six equal nine hours. Add the time you usually need to fall asleep, often around 10 to 20 minutes. For a 7:00 a.m. wake-up, five estimated cycles would place sleep onset near 11:30 p.m. and six near 10:00 p.m. Treat these times as flexible suggestions. A home calculation cannot determine your actual sleep stages, so prioritize enough total sleep rather than exact cycle completion.