Sleep cycle calculator
90‑min cycles + buffer → recommended bed/wake times

Inputs

Choose a wake-up time (or bed time). We add a fall-asleep buffer and 90‑minute cycles.

Pick one direction.
Local time on your device.
Typical: 10–20 minutes.
Many sources use ~90 minutes per cycle.
Fill inputs, then click Calculate.
Notes
• This is a rough guide, not medical advice.
• If you wake up mid-cycle you may feel groggy — try different options.
About / 關於

Sleep cycle calculator — Pick a wake-up time (or bed time) and get recommended options based on a fall-asleep buffer and ~90-minute sleep cycles. Shareable, browser-only MVP.

Example: Use this tool to sanity-check numbers quickly, then share the link if you need to discuss with others.

FAQ: (1) Does it upload my data? No—runs in your browser. (2) Can I share results? Yes—use the share link feature. (3) Is it authoritative? Treat it as a convenience, not professional advice.

睡眠週期計算 — 選起床時間（或上床時間），用入睡緩衝與約 90 分鐘週期，列出多個建議睡/起時間。可分享連結、純前端 MVP。

範例：用這個工具快速試算與對照結果，需要討論時再把連結分享給對方。

FAQ： (1) 會上傳資料嗎？不會，計算在瀏覽器內完成。 (2) 能分享結果嗎？可以，用分享連結。 (3) 準確嗎？請把它當作便利工具，不是專業建議。