People argue about the "perfect title length" as if it were a magic number. It is not. What matters is where YouTube cuts the title off — and whether your hook survives the cut. Here is the mechanic and how to write for it.
Desktop: YouTube displays roughly 100 characters before ellipsizing a title. Sidebar / suggested videos: shorter, often 55-70 characters. Mobile: even shorter per line and font size. In every place where a stranger decides whether to click, your first ~50-60 characters are the entire title.
Aim for 40-70 characters. Under 40 is fine when the idea fits; over 70 only when the first 55 characters already carry the hook. When in doubt, cut — and check how the title looks in your own mobile app before publishing.
Generate titles with the right length — freeLength-aware generation · scores every title on 4 dimensionsYouTube allows 100 characters technically. But the technical limit is not the useful limit — display truncation happens well before that on mobile and sidebars. The useful target is 40-70 characters with the hook in the first 55.
Longer titles do not directly hurt ranking, but they dilute the visible message: keywords past the truncation point are less effective, and viewers who do not read the whole title are less likely to click. Search intent is served by front-loaded keywords, not extra words.
Preview it on a phone in the YouTube app and in the sidebar on desktop. If the strongest claim is cut off in either place, it is too long for practical purposes. TitleForge flags length automatically and rewrites titles that would get truncated.