Sleep cycle planner

Calculate or press Enter for the first plan. Later edits update it immediately; an open comparison stays open. Reset restores 07:00, five cycles, 90 minutes per cycle and 15 minutes to fall asleep, and clears the result. Inputs are kept locally in this browser across navigation and reload; results are not saved. Compare cycle counts shows alternatives and highlights the selected count.

For a wake-up time, subtract cycle count × cycle length plus time to fall asleep. For a bedtime, add both. Assumed sleep duration excludes falling asleep; total time includes it. Days are relative to the day of the entered time. This clock model assumes exactly 24 hours per day, with no dates, time zones, daylight-saving changes or alarms. Whole-minute calculation limits are 30–180 minutes per cycle and 0–180 minutes to fall asleep, with 1–8 cycles. These are software limits, not health recommendations.

Actual sleep cycles and phases vary. This calculation cannot detect your sleep phase, prescribe your sleep duration or guarantee restorative sleep. Background: NIH/NHLBI: Sleep Phases and Stages (source checked 9 November 2026).