YouTube Chapter Builder

Build clean YouTube chapters in seconds. Paste rough notes or press **Alt+C** while reviewing a YouTube video to capture its current timestamp, then name and arrange each chapter in the popup. YouTube Chapter Builder understands common timestamp styles such as `1.20`, `1:20`, `80 sec`, `01 20`, `1m20`, and `00:01:20`. Times over one hour are formatted as `1:02:03`. Before you copy, the extension checks that your list starts at `00:00`, has at least three chapters, uses valid ascending timestamps without duplicates, includes a title for every chapter, and keeps each chapter at least 10 seconds apart. ### Features - Capture the current YouTube playback time with **Alt+C**. - Edit titles and timestamps inline; drag rows or use the move buttons to reorder. - Copy a YouTube-ready chapter list or Markdown. - Export TXT and CSV files. - Keep chapter data in local Chrome storage. No account, AI, analytics, cloud sync, or backend is used.