How Sleep Cycles Work

Sleep moves through repeating stages including light sleep, deep sleep, and REM. A full cycle often takes around 90 minutes, though this can vary slightly by person and age.

Why cycle timing helps

Waking between cycles can feel smoother than waking during deep sleep. This is why the Sleep Cycle Calculator suggests wake and bedtime windows based on cycle counts.

How to apply this tonight

Pick your target wake-up time, subtract 4, 5, or 6 cycles, and include your fall-asleep buffer. Then test and adjust over a week.

Tip: Build a regular sleep window to help your body clock stay consistent.