How it works
A walkthrough, end to end.
- 1
Pick whether you're choosing wake time or bedtime.
- 2
Enter the time and how long it takes you to fall asleep.
- 3
See up to 6 ideal options spaced by 90-minute cycles.
Reference
Sleep cycles
Each cycle is ~90 minutes. Waking at the end of a cycle (light sleep) feels more refreshing than mid-cycle.
Use cases
What you can do with this.
Better mornings
Wake up between cycles to feel less groggy.
Shift workers
Plan around 90-minute cycles in any schedule.
Travel jet-lag
Adjust bedtime around new wake time.
Naps
20–30 min (power nap) or 90 min (full cycle).
Student exams
Plan study/sleep around early starts.
FAQ
Frequently asked.
Average sleep cycle for adults. Individual cycles range 80–110 min.
5–6 cycles (~7.5–9 h) is typical for adults.
No. All math runs in your browser.
Most people take 10–20 minutes to fall asleep. Adjust the field for your norm.