Sleep cycle calculator
when to sleep or wake to finish on a cycle boundary
Parameters
Go to bed at
21:456 cycles ≈ 9 h
23:155 cycles ≈ 7.5 h
00:454 cycles ≈ 6 h
02:153 cycles ≈ 4.5 h
Highlighted are the recommended 5–6 cycles (7.5–9 h) for adults.
The average sleep cycle is ~90 min (80–110 across people). Waking at a cycle boundary feels easier than during deep sleep. This is an averaged model — your actual cycle length is individual.
About Sleep cycle calculator
Sleep cycle calculator — when to sleep or wake — 90-minute sleep cycles. Health: Health calculators. Use our tools without registration or installing software. All calculations happen in your browser — your data is never sent to a server.