Everything you wanted to know about sleep, cycles, and why we do not collect your data.
Yes. All calculations happen in your browser. We do not have a database. We cannot see your bedtime, your sleep debt, or anything else you enter. Your data is stored in your browser's localStorage, which you can clear anytime.
It is an average. Individual cycles range from 80 to 120 minutes depending on age, genetics, and sleep quality. Our calculator shows you a range of optimal bedtimes, not just one.
Our tools help you understand patterns, but they are not a treatment for sleep disorders. If you have chronic insomnia, please see a board-certified sleep specialist or a CBT-I therapist.
No. We do not have user accounts, login systems, or password recovery. Your data is stored locally in your browser using localStorage.
Yes. All tools are free to use. We may show sponsored content to cover hosting costs, but the tools themselves will always be free.