We built this tool to help you sleep smarter — not just longer. By timing your sleep to natural 90-minute cycles, you can wake up feeling genuinely rested regardless of how many hours you get.
How it works
Sleep cycles are 90 minutes long
Your body moves through repeating cycles of light sleep, deep sleep, and REM sleep. Each cycle takes roughly 90 minutes. Waking mid-cycle — especially during deep sleep — causes that groggy, disoriented feeling. Waking at the end of a cycle, when sleep is naturally lighter, means you feel alert right away.
When you sleep matters, not just how long
8 hours starting at midnight feels different from 8 hours starting at 10 PM. Your body's circadian rhythm makes earlier sleep more restorative — particularly the hours before midnight. That's why our score weights them higher.
The sleep score
Not all sleep hours are equal
We assign points per hour based on when you're sleeping — reflecting how restorative each time window tends to be:
Score interpretation
Tips for better sleep
Sleep hygiene
Using this calculator