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About this tool
Check one caption against every platform's character limit and truncation point, including X's 23-character URL rule.
Caption Length Optimizer measures one caption against the hard character limit and the visible-before-"more" fold of every major social platform at once. It counts by code point so an emoji costs one character, applies X's rule that any link counts as a fixed 23 characters after t.co wrapping, and shows the exact words that survive above each platform's fold. Limits covered include Instagram's 2,200, X's 280, LinkedIn's 3,000, Threads' 500 and a YouTube title's 100.
Open Caption Length Optimizer on AltFTool — it loads instantly in your browser.
Paste or type the text you're working with.
Choose how it should be transformed or analyzed.
Copy the finished text into your document or post.
One caption checked against twelve limits and fold points, with a per-platform pass or fail.
X charges 23 characters per URL regardless of length; that is applied automatically.
Each platform shows the exact visible slice, so you know whether the point lands before the cut.
2,200 characters, but only about the first 125 show in the feed before "... more". Instagram also rejects a post carrying more than 30 hashtags, and hashtags count toward the same 2,200 characters.
280 characters on a standard account and 25,000 with Premium. Links are the catch: every URL is wrapped by t.co and counted as exactly 23 characters, so a 90-character link still only costs 23.
The limit is 3,000 characters, and the feed collapses the post behind "...see more" at roughly 140 characters on mobile — earlier than on desktop. Front-load the claim in the first line or most readers never expand it.
It depends on the platform's counting method; this tool counts by Unicode code point, so a standard emoji costs one. Multi-part emoji such as flags or skin-tone and family sequences are made of several code points and can cost more, so leave a little headroom when a caption is right at the limit.