Caption Analyzer & Paste Safety Check

Counts your caption the way a reader counts it and the way the platform counts it — those are different numbers — shows where the feed will cut it off, and finds the invisible characters that break a post after you paste it.

Hashtags, mentions and links

Paste safety

Characters that look fine on screen but are not what they seem. These survive a copy and paste and then break a link, split a hashtag, or make a handle point somewhere other than where it reads.

Alt text

The description read aloud to anyone using a screen reader. Checked for the handful of things that go wrong most often; nothing here can tell whether it describes the actual picture.

Why three different character counts

Ask how long 👨‍👩‍👧‍👦 is and there are three defensible answers. To a reader it is one character. Underneath it is seven code points — four people joined by invisible glue. And in the units JavaScript counts by default it is eleven.

Almost every word counter on the web reports that last number, because text.length is the obvious thing to write and it is wrong for anything outside the basic Latin range. On a caption with a dozen emoji the error is large enough to matter: you are told you are near the limit when you have hundreds of characters spare, or under it when you are not.

So all three are shown here, with the human count first. The limit for each platform is labelled with the unit it is actually enforced in — on X a link costs a flat 23 characters however long it is, and most emoji and CJK characters count double.

What paste safety is really about

Text written in a word processor and pasted into a post carries things you cannot see. Curly quotes and en dashes are the visible ones. The invisible ones are worse: a zero-width space inside a URL means the link simply does not work, and no amount of staring at it will show you why.

Curly quotes, em dashes and ellipses are listed too, but they are not faults — they are what good typography looks like, and a caption is the right place for them. They only matter where something has to match exactly, which is why straightening them is a choice rather than the default.

Two findings are worth treating differently from the rest. A bidirectional override reorders how text displays, so what you read is not what the characters say — the trick behind filenames that appear to end in .txt. And a confusable is a letter from another alphabet that renders identically to a Latin one: the Cyrillic а in what looks like paypal.com is a different character, and the link goes somewhere else entirely. Both are flagged as deceptive rather than merely untidy.