YouTube chapters checker and timestamp formatter

What this tool does

You wrote timestamps in your description and YouTube still shows them as plain links, with no chapters on the progress bar. This tool reads your list, checks it against the rules YouTube publishes, and tells you which rule is broken and on which line. Where the fix has one clear answer, a button applies it. You then copy a clean list and paste it back.

It also converts editor markers. If you dropped markers on your timeline in DaVinci Resolve, Premiere Pro or Final Cut Pro, export them, drop the file here, and the timecodes become YouTube timestamps. Everything runs in your browser. Your description and your marker file are never uploaded.

What else belongs in the description is covered in the free course lesson descriptions, chapters, and tags that matter.

How to use it

1. Paste. Paste your timestamps, or your whole description, or drop a marker file. You get a line that says what the tool read and how many chapters it found. Lines that are not chapters are left alone.
2. Read the check. Each broken rule is shown in YouTube's own words, with the line that breaks it. You get a button for each fix that has one clear answer: add a 0:00 chapter, sort by time, or merge a chapter shorter than 10 seconds into the one before it. If you would rather keep that title, edit the line in the box instead.
3. Add the video length (optional). Type it as 12:34. You get the length of every chapter, its share of the video as a bar, and a warning when a timestamp sits past the end.
4. Choose the format. Pick the timestamp style, a space or a dash before the title, and the title clean-up. You get the finished list and its size in bytes against the description limit.
5. Copy and paste. Copy the chapter list, or copy the whole description with the chapter lines replaced in place. Paste it in YouTube Studio under Content, your video, Description, then save. Chapters are one line of the pre-publish checklist.

The rules this tool checks

These are the facts the checker is built on. Each row is quoted or taken directly from the source named next to it.

Two things the Help page does not say, so this tool does not present them as rules. It writes the first timestamp as 00:00 and does not list which other spellings are accepted. Lists that start with 0:00 are common on videos with working chapters, but that is an observation, not a published rule, so the default style here is 00:00. It also gives no maximum number of chapters.

Importing markers from your editor

Markers are easier to place when the cut already follows a plan. See edit the story before the timeline.

Editors count in timecode: hours, minutes, seconds and frames, such as 01:02:10:12. YouTube counts in whole seconds from the start of the video. The tool removes the timeline start, drops the frames, and rounds down so a chapter never starts after its marker.

Frame rate matters less than you would think, and more at 23.976. At 24, 25, 30, 50 or 60 fps the frame rate only decides how the frames part rounds. At 23.976, 29.97 and 59.94 fps without drop-frame timecode, the timecode runs slower than the clock: one hour of timecode is 3,603.6 real seconds, so a marker late in a long video is up to 3.6 seconds off per hour if you pick the wrong rate. Drop-frame timecode, written with a semicolon before the frames, is detected and handled.

Timeline start. Resolve timelines start at 01:00:00:00 unless you changed it. When every marker in the file sits at or after the one-hour mark, the tool assumes that start and removes it. If your first marker really is more than an hour into a timeline that starts at zero, set the start to 00:00:00:00 yourself.

A worked example

Press "Try an example" to load this one. The video is a 20:14 desk build and the paste is eight lines in five different shapes:

- 0:42 Why the old desk had to go
* 02:10 - Measuring the room.
Buying the wood (4:35)
[6:20] Cutting list
6:26 | first cut
11:05 Glue up and clamps...
14:48	Sanding, oil and legs
1) 18:30 The finished desk

The tool reads all eight lines and finds two broken rules. The first timestamp is 0:42, not 0:00. And "6:20 Cutting list" runs for 6 seconds, because the next chapter starts at 6:26, which is under the 10 second minimum. Either one is enough to stop every chapter from showing.

The two fixes: add a 0:00 Intro chapter, and merge the 6 second "Cutting list" into the chapter before it, so "Buying the wood" runs until 6:26. The list you copy has eight chapters and passes every rule:

00:00 Intro
00:42 Why the old desk had to go
02:10 Measuring the room
04:35 Buying the wood
06:26 first cut
11:05 Glue up and clamps
14:48 Sanding, oil and legs
18:30 The finished desk

With the length typed in, the longest chapter is "first cut" at 4 min 39 s, 23% of the video, and the shortest is the 42 second intro.

What this tool does not do

• It does not watch your video or write chapter titles for you. It works with the timestamps and titles you give it. Good chapter points come from the structure of the video, which is what how to write a video script is about.
• It cannot see your channel. If the list passes and chapters still do not show, check for an active strike, and give YouTube a little time after saving.
• It does not publish anything. You paste the result into YouTube Studio yourself. Once it is live, end screens, cards, and playlists are the next step.
• It does not check Shorts or live streams. The Help page describes chapters for regular videos.
• The Final Cut Pro import is best-effort, as the table above says.

If you plan videos in Vanpelt Studio, the desktop app exports your beat markers for the editor, so the chapter points are already on the timeline when you start cutting.