YouTube Description Generator & SEO Checker

The description is the readable part of your video

YouTube cannot watch your video. Neither can Google. Both of them work out what it is about from the text you attach to it — the title, the description, the chapter names and, to a much smaller degree, the tags. Your thumbnail wins the click; the description is most of what decides whether the click is ever offered.

This tool checks the whole of that text at once, in your browser, as you type. Nothing is uploaded, so an unpublished description for a video that goes live next week is safe to paste in.

The first 150 characters do nearly all the work

YouTube collapses the description to about two lines under the title, with a “…more” link after it. Google builds its search snippet from roughly the first 160 characters of the same text. Almost nobody expands the box, and the search engines that do have already weighted the opening most heavily.

So the opening line has one job: say what the video is, in the words someone would have typed to find it. Both mock-ups above show you exactly where the cut falls — including the trap of a short first line, because a line break in your description ends a line in the collapsed box too.

Chapters are the highest-value thing in the box

A valid list of timestamps turns into named chapters on the progress bar, into separate sections in YouTube's search results, and into key moments in Google. It is the closest thing to free distribution the description has, and it works only if you follow three rules exactly:

• The first timestamp must be 00:00. Not 00:05, not "intro at 0:03".
• You need at least three timestamps, in ascending order.
• Every chapter must run at least 10 seconds.

Break any one of them and YouTube silently ignores the entire list — the timestamps stay as plain clickable links and you never get told why. The checker applies all three and points at the exact line that fails.

Hashtags, links and tags

The first three hashtags in your description appear as links above your title; the rest sit there doing very little. Go past 15 on a video and YouTube discards all of them, not just the extras. Links belong below the fold — a URL in your first sentence spends the one piece of space that has to sell the expand.

Tags are the weakest signal of the lot, and they still have a hard 500-character budget across the whole set. The tags panel shows you which ones fall past it and get dropped, flags duplicates, and checks your exact keyword is in there. Ten to fifteen honest tags is the whole job.

Where this sits in the workflow

Check the other half of the package with the title checker, which shows where your title is truncated on every surface. Then make sure the thumbnail earns the click with the thumbnail preview. If you are optimising for search specifically, the guide to where your views actually come from is worth reading first — search is only one of the doors.

Last updated August 27, 2026.