People decide whether to read a caption before they read it, from how it looks. A solid block of text looks like work; the same words in short pieces look like a conversation.
What to do
- Start with the line that earns the rest. Everything after the first line or two sits behind “more”.
- Break after every one to three sentences. One idea per block.
- Use a blank line between sections, not a row of dots.
- Put list items on their own lines, one each, with a dash or an emoji at the start.
- End with the ask or the point, and then stop.
What breaks
Formatting you cannot see in your tool can change on the network. Line breaks are the usual casualty: a caption with clean paragraphs in the editor can arrive with fewer blank lines than you wrote, or with extra, depending on where it is published. Bold and italics generally do not exist in captions at all, so asterisks and underscores just show up as symbols.
Preview, then trust it
Look at the preview for the network you are posting to. It will not be perfect, but if the preview shows a wall, the post will be a wall; if it shows clean breaks, you are mostly fine. Publishing a test to yourself costs a minute and saves correcting a live post.
A length to aim for
As long as the thing needs, and no longer. A caption can be one line or twelve; what hurts is length without shape. If you cannot see where one idea ends and the next begins, neither can the reader.
Squint at the caption. If it looks like a grey rectangle, add a blank line before you do anything else.