Sleep Cycle Calculator
Wake up refreshed by timing your sleep to natural 90-minute cycles.
✦ Includes 14-minute sleep onset buffer
🌀 What is a sleep cycle?
Every 90 minutes, your brain completes a full cycle through distinct stages of sleep. Waking mid-cycle leaves you groggy - waking at the end of one feels effortless.
6 cycles = 9 hours · each block = 90 min
The 14-Minute Buffer
The average person takes 14 minutes to fall asleep. All times above account for this - so you truly wake at the end of a full cycle.
⭐ Why 5-6 cycles?
REM periods lengthen with each successive cycle, so the later cycles carry most of your memory consolidation and emotional processing.
Five cycles (7.5 hours) is the minimum most adults need for full cognitive recovery; six cycles (9 hours) aligns with guidelines from major sleep research bodies.
Waking at the end of a cycle means surfacing from light sleep, which produces less sleep inertia than waking from deep slow-wave sleep.
Read our in-depth guide on the science of sleep cycles →
