Bedtime & Sleep Cycle Calculator
Work back from your alarm in 90-minute sleep cycles.
Bedtimes (from tonight)
Sleep runs in ~90-minute cycles; waking between cycles feels far better than mid-cycle. Times include your “fall asleep” lag — go lie down at one of these and aim for 5–6 cycles (7.5–9 h).
使用方法
- 一切都在您的浏览器本地运行：不会上传任何数据，无需账户。
关于
Pick your wake-up time and how long falling asleep takes you; the calculator lists bedtimes at whole sleep cycles of 7.5 and 9 hours, plus shorter options.
Waking mid-cycle groggy but at the top of a cycle refreshed is well documented — the 90-minute rhythm is the reason 6 hours can feel better than 7 hours 10 minutes.
一切都在您的浏览器本地运行：不会上传任何数据，无需账户。
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