Bedtimes and wake times built around 90-minute sleep cycles.
Sleep runs in roughly 90-minute cycles. This tool counts back or forward in whole cycles (4 to 6 cycles, 6 to 9 hours) and allows about 15 minutes to fall asleep. It is a planning guide, not medical advice.
No. 90 minutes is an average cycle length. Real cycles vary by person and night, so treat the times as a guide.
Sleep Cycle Calculator is a free online tool from Daily Tools. The Sleep Cycle Calculator suggests times to go to bed or wake up so you wake at the end of a sleep cycle, when waking up usually feels easier. Like every tool on this site, it runs entirely in your browser: there is no sign-up, nothing you type or upload is sent to a server, and it works the same on a phone, tablet or desktop. Bookmark this page to come straight back to the Sleep Cycle Calculator whenever you need it.
Questions or a wrong result? Email bingeul29@gmail.com with the tool name and what you entered.