Field notes
Playbooks, teardowns and the occasional argument — everything we have learned helping creators grow across every major platform.
No platform limits the text on a carousel image. What limits it is whether anybody can read it at feed size, which makes the answer arithmetic rather than a rule.
All three answers are correct. Which one applies depends on who is counting, and the gap is why a caption that looks fine gets rejected by the form before the platform sees it.
Everything after the fold is read by people who already decided to read. The first line is the only part that talks to everyone else, and it is usually the part written last.
Two posts is never a result. The confounds - time, day, subject, an audience that has already seen one version - are larger than any caption effect you are looking for.
The two style guides agree about almost every word in almost every title. The exception is prepositions of four letters or more, and that single rule is the whole difference.
A crutch phrase is invisible inside one post by definition. You cannot find it by re-reading more carefully - you find it by putting thirty posts next to each other.
Jargon is not bad writing, it is expensive writing. It buys precision from people who share the vocabulary and charges everyone else the cost of looking something up.
Nothing is wrong with the words. There are just fourteen sentences in a row of between twelve and sixteen, and an average is the one statistic that cannot see it.
The 100-character limit is the number the upload form enforces. The numbers that decide whether anyone reads your title are 70, 60 and 40, and nothing mentions those.
A Japanese post with 140 characters in it is at the limit, not halfway to it. X weights CJK characters as two, which is why a shorter caption can be the one that overflows.
Every published expansion table gives one percentage per language. The number that decides whether your caption fits is not that one - it is how short the English was to begin with.
The translation is the easy part. What catches people out is that the caption no longer fits, the hook is now below the fold, and the hashtag reaches a different set of people entirely.