YouTube chapter generator and timestamp checker

What this tool does

You bring the timestamps and titles. The tool turns whatever you pasted into one tidy list, then tells you what YouTube is likely to reject before you save the description. It accepts common layouts such as 0:00 Intro, [00:00] Intro, 00:00 - Intro, a numbered list, and Intro - 00:00.

• Rewrites every time as 00:00 or 1:02:03 and sorts the list by time.
• Checks the chapter rules and shows each problem with its line number.
• Shows the length of every chapter, so a too-short one stands out.
• Fixes the common mistakes in one click: sort, add a 00:00 chapter, drop chapters that are too close together.
• Moves every chapter earlier or later by a number of seconds, for when you trim or extend the start of the video.
• Counts characters, because the whole description has a limit.

It does not listen to your video and it does not suggest chapter titles. If you need a transcript first, the transcript cleaner is a good companion. Your text is processed in this tab only: there is no upload, no account and no network request.

How to use it

1. Paste your list into the box, one chapter per line, or press Try an example.
2. Optional: type the video length, such as 42:10. The tool then also checks that the last chapter is long enough.
3. Read the results. A red Problem means YouTube is likely to ignore the list; an amber Check is only a suggestion.
4. Use a quick fix if one is offered, then read the list again. The fixes rewrite the box from the lines that have a valid time.
5. Press Copy list, open the video in YouTube Studio, paste the list into the Description and save.

The rules it checks and where they come from

YouTube's help page on Video Chapters lists the requirements for adding your own chapters. The tool applies exactly those, plus the description length limit from YouTube's upload page. Both pages were read on 11 October 2026.

What it does not check

• Whether YouTube will show chapters. The help page says chapters may need access to Advanced features, and that automatic chapters are not available if the channel has active strikes or the content may be inappropriate to some viewers. A passing list is necessary, not a promise.
• Hour formatting. The help page shows only the 00:00 form for the first timestamp. The tool writes hours as 1:02:03, so check that the chapters appear after you save.
• Link timestamps. YouTube's Share panel has a Start at box for linking to a time, with 2:30 as its example. The tool does not build links, because the help page does not spell out a link format.
• Character limits in the API. The API documents the description limit as 5000 bytes rather than characters. The two differ for text with accented letters or emoji. Studio, where most people paste chapters, says 5,000 characters, and that is what the counter uses.

Adding your own chapters replaces automatic ones, according to the same help page. If you want YouTube's automatic chapters, leave the description without a timestamp list.

Worked examples

First, a list from a 26-minute episode, pasted as it came out of a notes app. The checker finds one problem: the chapter at 12:45 is only 5 seconds long because Side note starts at 12:50.

Second, a list written while watching a rough cut. It starts at 0:45, so the first rule fails. Add 00:00 Intro keeps all three chapters and puts a new first line above them. Move first chapter to 00:00 keeps the line count and changes 0:45 Cold open to 00:00 Cold open. Pick the second when the video really does open with that topic.

Third, a shift. You wrote chapters on a draft, then added a 15-second cold open to the front. Chapters at 00:00, 02:00 and 05:00 become 00:15, 02:15 and 05:15 when you press Later with 15 seconds. The first line is no longer 00:00, so add the start chapter. Moving earlier works the same way, and any chapter that would land before 00:00 is removed and reported.

Decision rules for a messy list

• If two chapters are under 10 seconds apart, they are one topic. Keep the better title and drop the other.
• If you have only two topics, you have two chapters. Find a third point where the subject shifts, or leave chapters off.
• If the first chapter is the real start of the video, use Move first chapter to 00:00. If there is a gap before it, use Add 00:00 Intro.
• If you paste a list with notes between the lines, they are left out and the tool tells you which lines it skipped.

Chapters are also a map for clipping

A chapter list marks where a long episode changes subject. Those are natural places to look for a short clip: each chapter is a topic that already has a start and a stop. That is the one place this page touches what KeyMo does. KeyMo takes a long video and returns up to 15 vertical 9:16 clips, each with a score out of 10, and keeps only the clips that score 7 or higher. It does not read your chapter list, and this free tool does not need an account. If you are working out which sections to cut, see how to clip part of a podcast.