Copy-pasting the same caption everywhere wastes the post on most networks. Here is what to change for Facebook, Instagram, LinkedIn, X, TikTok, YouTube and Pinterest, with each network's documented limits.
Write the core of the post first: one sentence that says what is new or useful, one detail that makes it concrete, and one action. Everything below is about packaging that core for each place.
| Network | Length that matters | Links | Hashtags | Media |
|---|---|---|---|---|
| Short works best, even though long posts are allowed | Clickable; a link card shows when there is no image | A few at most | Images or video help | |
| Up to 2,200 characters; the first line shows before “more” | Not clickable in captions | Up to 30 allowed; a handful focused ones read better | Required | |
| Up to 3,000 characters in PostRoost; the first two lines decide | Clickable; article card without images | Two or three | Optional | |
| X | 280 weighted characters; links count 23 | Clickable, count 23 each | Sparingly | Up to 4 images or a video |
| TikTok | Caption up to 2,200 (UTF-16 units) | Not allowed | Common | Video or photos required |
| YouTube | Title up to 100 characters, description up to 5,000 bytes | In the description | In the description | Video required |
| Title up to 100, description up to 500 in PostRoost | One destination link per Pin | Few | One image per Pin |
Limits for X, Instagram, TikTok and YouTube come from each network’s developer documentation (see sources). For Facebook, LinkedIn and Pinterest we could not find a current official reference, so the numbers are the limits PostRoost’s composer enforces.
Facebook. Keep the point in the first two lines. If you share a link without an image, Facebook builds a link card from the page; check the page’s preview image looks right.
Instagram. The image does the work; the first line of the caption is the hook. Put links in your bio or a link-in-bio page and say so. Use the first comment for extra hashtags if you prefer a cleaner caption.
LinkedIn. Lead with the insight, not the announcement. Short paragraphs, plain language, two or three hashtags. Tag people only if they will recognise why.
X. Cut to the essentials. A link costs 23 characters wherever it is, so you can move it into a scheduled first reply and use the full post for the message.
TikTok. The video carries the post; the caption adds context and hashtags. No links.
YouTube. Write the title for search: what the video is about, in under 100 characters. Put details, links and chapters in the description.
Pinterest. Pins are found through search: a descriptive title, a helpful description and a link to the exact page the image is about.
Paste the final caption into our character counter to see every network’s limit at once. In PostRoost, the composer’s per-network tabs show the same counts as you type.
Facts on this page were checked against the sources below on .
10 questions
It is rarely the best use of a post. Length, links, hashtags and media work differently on each network, so the same text can be cut off, lose its link or look out of place.
Neither makes caption links clickable, and TikTok does not allow them. Point people to the link on your profile and say so in the caption.
Instagram allows 30, but a handful of focused ones read better; TikTok uses them commonly; LinkedIn two or three; X and Facebook sparingly. Pinterest relies more on descriptive text.
The opening line. Each network shows only the start before "more", so lead with what matters for that audience.
On LinkedIn, lead with the insight, use short paragraphs and up to 3,000 characters. On X, cut to the essentials and move the link to a reply to free up space.
100 characters, and the description up to 5,000 bytes without angle brackets. Write the title for search: what the video is about.
Ideally, yes, at least different crops. Instagram and TikTok need media, YouTube needs video and Pinterest takes one image per Pin.
No. Alt text describes the image, so it stays the same wherever the image goes. Write it once and reuse it.
Paste the caption into our character counter, which shows all seven networks side by side.
In PostRoost, you write once under All networks and change only what each network needs in its tab. The AI assistant can draft a per-network version from a brief, which you then review.
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