Overview
90-minute sleep cycles explained. Calculate when to sleep and wake for less grogginess.
Count backward from the time you must be awake, in 90-minute blocks, and treat the result as a bedtime window, not a medical rule.
How to use it
- Open Meditation Timer.
- Set the minutes, test the chime at a low volume, and start only after you are settled.
- Keep Power Nap Alarm or Breathing Timer for a second phase.
Good to know
Do not use a browser chime as a medical alarm. For rest or breathing, stop if you feel unwell.
The tools are free on the TimerClock home page. Settings stay in this browser. The privacy policy explains what is stored.
Frequently asked questions
What is this guide for?
90-minute sleep cycles explained. Calculate when to sleep and wake for less grogginess.
Which TimerClock page should I open?
Start with Meditation Timer. Use Power Nap Alarm when you want a closer variation.
What length should a beginner use?
Start with the shorter end of the range in this guide. A finished short session beats an abandoned long one.
Will a quiet chime be enough?
Test it in the room you use. A soft tone is easy to miss next to a fan or a street window.
When was this guide updated?
October 2, 2026. The steps match the tools linked on this page.