Character limit checker

Almost every field on this page has two limits, and it is the second one that decides whether anything you wrote gets read. Instagram accepts 2,200 characters of caption and shows about 125 before "more". YouTube accepts 5,000 and shows about 150. LinkedIn takes a 3,000-character post and folds it at roughly 210. The ceiling is rarely what goes wrong. Writing the first 125 characters as though nobody will stop there is.

Two things count that people do not expect

A line break is a character. The tidy four-line bio everyone likes spends three of its 150 on the breaks between those lines before a single word goes in. And an emoji displays as one character while a platform usually counts it as more, which is the answer to "why is my bio rejected when I counted exactly 150". This counter treats an emoji as one, so if a field refuses something it says fits, that is the first place to look.

Instagram

The 150-character bio has a trap that costs nothing to avoid: only the link field is clickable. A URL typed into the bio text is plain text that spends characters and does nothing. On captions, the 125-character fold means the opening line is the whole caption for most of the audience, so an opening greeting spends the visible portion on nothing, and hashtags placed at the top consume it entirely. That is the argument for putting them at the end or in the first comment. The widely repeated claim that comment hashtags outperform caption ones has never been demonstrated, and Instagram has said the two are treated the same. Thirty hashtags is the limit across the caption and first comment together. Instagram also strips whitespace-only lines, which is why the paragraph breaks people carefully insert vanish on posting.

Google Ads

Google Ads is the odd one out, because going over does not truncate. It rejects the ad at upload, so nothing runs until you shorten it. Thirty characters is short enough that most of the work is deciding what to leave out, and two habits genuinely help: spaces count, so an ampersand instead of "and" buys two characters and reads fine in an ad, and a numeral beats a spelled-out number, since "5" against "five" saves three characters and tests better besides. With responsive search ads there is a harder constraint than the count. You supply many headlines and Google assembles the combinations, so each one has to make sense on its own and beside any of the others.

Email

Thirty-five characters is roughly five words, which is far less room than it feels like at a desk. The preview text beside the subject is the underused half: most clients show 40 to 90 characters of body text after it, and leaving that to be filled by "View this email in your browser" wastes the most valuable line in the inbox. Set it deliberately with a preheader. Two habits to drop regardless of length: capitals throughout and stacked exclamation marks both correlate with spam filtering, and an RE: or FW: prefix on a message that is neither costs more trust than it wins opens.

LinkedIn, TikTok, YouTube and Pinterest

On LinkedIn the truncation is the whole game. Your headline appears in full on your profile and nowhere else; in search results, comments, connection requests and the feed it is cut to roughly 60 characters on desktop and fewer on mobile. So the useful structure is the important thing first and the qualifiers after, and a headline that opens with a keyword list and reaches the point at character 140 is invisible everywhere it matters.

A TikTok caption sits over the video instead of beside it, so every character covers the thing people came to watch. A long caption there goes beyond unread and becomes an obstruction. The counterweight is that TikTok indexes caption text and TikTok search gets heavy use, so stating plainly what the video is has real discovery value inside the first hundred characters.

YouTube folds at about 150 and almost nobody expands, which makes the first two lines the practical description and the remaining 4,850 characters a place for chapters, links, credits and disclosures instead of persuasion. Chapter timestamps are the part worth the effort: a properly formatted list beginning at 0:00 creates chapter markers on the progress bar. Links in a description are not clickable until the channel is verified.

Pinterest is the one platform where writing the full 500 characters pays despite the truncation, because it works like a search engine and indexes the whole description. A pin surfaces on search for months or years where a post surfaces on a feed for hours, so the text keeps working long after the visible 50 characters have stopped mattering. Write the opening for a human scrolling and the remaining 450 for the index. That is the opposite of the advice for everything else here, and it is why the same copy pasted across platforms underperforms on Pinterest.