About this sleep cycle calculator
An adult sleep cycle averages about 90 minutes, and falling asleep takes around 15. The tool projects wake-up times after 3–6 cycles from now (now + 15 min + cycles × 90 min), or works backwards from a fixed wake-up time to suggest four bedtimes. Six cycles — about 9 hours — is the recommended target.
Waking at the end of a cycle usually feels easier than being woken mid-deep-sleep, but individual sleep latency and cycle length vary, so adjust to how sleepy you feel. Results are for routine planning only and are not medical advice; all times are computed locally in your device's time zone.