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About this tool
Assemble a reusable YouTube description with validated chapters, links, hashtags and disclosures inside the 5,000 character limit.
YouTube Description Template Builder assembles a complete, reusable description — summary, chapters, links, credits, disclosures and hashtags — and validates it against YouTube's own rules while you type. It enforces the 5,000-character description limit, the chapter requirements (first timestamp at 0:00, at least three chapters, each running 10 seconds or longer) and the 15-hashtag ceiling above which YouTube ignores every hashtag on the video.
Open YouTube Description Template Builder on AltFTool — it loads instantly in your browser.
Add your input to the workspace.
Adjust the options until the result looks right.
Copy or download the output and put it to work.
Timestamps are parsed, sorted and measured, and every rule YouTube applies is reported as a specific fix.
Live character count against the 5,000 limit, plus a preview of what shows before the fold.
Paid promotion, affiliate, gifted product and synthetic media blocks are one checkbox each.
5,000 characters, including spaces and line breaks. Only about the first 100 characters show on the watch page before the "...more" fold, and roughly the first 157 appear in search results, so the important line has to come first.
The three most common causes are a first timestamp that is not 0:00, fewer than three timestamps in the list, and a chapter shorter than 10 seconds. Timestamps must also be in ascending order and each needs a title on the same line, in the form "1:24 The setup".
Three to five is plenty, and only the first three appear above the video title. Going over 15 hashtags on one video causes YouTube to ignore all of them, so a long tag dump does nothing.
Yes, and you should also tick the paid promotion box in YouTube Studio — a description line alone is not the full requirement. Advertising rules vary by country and by affiliate programme, so confirm what applies to you rather than relying on generic wording.