Key takeaways
- Caption limits range from around 280 characters (X) to over 60,000 (Facebook) — plan copy for the shortest platform you're posting to if reusing text.
- Vertical 9:16 video is now the standard short-video format across TikTok, Reels, and Shorts.
- Platforms periodically change these limits — treat exact numbers as approximate and verify before a launch that depends on them.
- A validation step before publishing catches spec mismatches before they cause a failed post.
Social media posting rules by platform: facebook
Facebook's caption limit is very high (over 60,000 characters), though posts that are actually read in full tend to be much shorter — a few hundred characters at most for a typical Page post. Image posts commonly use a 1200×630px landscape image; native video performs best at under two minutes, uploaded directly rather than linked.
Instagram captions are capped at 2,200 characters, though only the first couple of lines show before "more". Feed images typically use a square (1080×1080px) or portrait (1080×1350px) ratio; Reels and Stories use vertical 9:16 video, with Reels supporting videos up to a few minutes long.
LinkedIn post text is capped at 3,000 characters, with only the first roughly 200-210 characters shown before "see more" truncates it — that first line is effectively the headline of the post. Native documents (PDF carousels) support multiple pages; video is capped around 10 minutes for organic posts, though shorter native video tends to perform better.
TikTok
TikTok captions are capped around 2,200 characters. Video must be vertical 9:16 to display properly in the main feed; supported lengths have expanded over time and now reach well beyond a minute, but shorter, tightly edited videos in the 15-60 second range remain the most reliable format for reach.
X (formerly Twitter)
X's standard caption limit is 280 characters for most accounts (higher for X Premium subscribers). Images commonly use a 16:9 landscape ratio; video is capped at 2 minutes 20 seconds for most accounts.
Why this matters for cross-posting
The gap between X's 280-character limit and Facebook's effectively unlimited one is the clearest example of why the same caption rarely works unedited across every platform. A validation step that checks each post against the target platform's actual limits — before scheduling, not after a failed post — catches these mismatches early, which is exactly what SkedCast's row-level validation does during a bulk import.
FAQ
- What is the character limit for each major platform?
- Roughly: X 280 characters, LinkedIn 3,000 (with ~200-210 shown before "see more"), Instagram 2,200, TikTok ~2,200, and Facebook over 60,000. These limits change occasionally, so treat them as approximate.
- What video format works across the most platforms?
- Vertical 9:16 video is now the standard short-video format across TikTok, Instagram Reels, and YouTube Shorts, making it the safest single format to produce if the same video needs to go to all three.
- How do I avoid a post failing because it breaks a platform's rules?
- Validate each post against its target platform's specs before scheduling — caption length, media dimensions, and file type — rather than discovering a rule violation after a scheduled post fails to publish.
- Where can I find official social media posting guidelines for each platform?
- Each platform's help center publishes its own current caption limits, media specs, and content policies; the numbers above are a practical working reference, but treat platform-published guidelines as the source of truth since limits change occasionally.