01
The three rules YouTube checks
YouTube turns timestamps in a description into chapters only if the first one is 00:00, there are at least three in ascending order, and every chapter is at least 10 seconds long. If one line breaks a rule, YouTube doesn't show a single chapter, so one stray timestamp in a long list is enough to lose all of them.
With the video length filled in, the tool also checks the last chapter: it starts the clock at the final timestamp and needs 10 seconds before the video ends.
02
What the fix changes, and what it doesn't
Sort and fix puts the chapters in time order, drops a second line with the same timestamp and adds a 00:00 chapter if the list doesn't start there. It doesn't merge chapters that are too short, because deciding which title stays is up to you.
The copied list uses one format for every line (01:05, or 0:12:05 once the video passes an hour), so it lines up in the description.
03
Writing chapter titles people click
Chapters show up on the progress bar and, for many videos, in search results as key moments. Short, specific titles work best: "Choosing a grinder" says more than "Part 2". Keep the first chapter short too, since viewers who skip the intro land straight on the second one.
Sources and methodology
Numbers checked on October 18, 2026.
The three rules (first timestamp 00:00, at least three in ascending order, each chapter at least 10 seconds) come from YouTube Help. Lines are read in the order you pasted them, the same way YouTube reads the description. Everything runs in your browser.
- Video chapters (first timestamp 00:00, at least three, each 10 seconds or longer) — YouTube Help, October 18, 2026
