TL;DR There is no single "perfect length." But every platform has a range where engagement tends to peak — usually well below the character limit. Twitter/X: 71-100 characters. Instagram captions: 138-150 for quick posts, longer for carousels. LinkedIn: 1,200-1,500 characters. Facebook: 40-80 words. This guide covers 12 platforms with the actual numbers, not just vague advice.
The character limit tells you the maximum. It does not tell you the optimum. Those are different things, and confusing them is one of the most common mistakes in social media writing.
Every platform has a point where engagement — likes, comments, shares, saves, clicks — tends to peak. That point is almost always well below the maximum. A LinkedIn post can hold 3,000 characters, but the posts that get the most engagement typically land between 1,200 and 1,500. An Instagram caption can stretch to 2,200 characters, but the data consistently shows that shorter captions (138-150 characters) get more engagement on standard feed posts.
This guide covers 12 platforms. The numbers below are engagement-optimized lengths based on published research and platform data, not arbitrary rules. Use the character counter to check your text against these ranges before posting.
One important caveat upfront: content type matters more than a rigid number. Educational content can run longer because the audience expects depth. Promotional content should run shorter because nobody wants to read a long ad. The ranges below are starting points, not laws.
The summary table
| Platform | Engagement-Optimized Length | Character Limit | Notes |
|---|---|---|---|
| Twitter / X | 71–100 characters | 280 | Posts under 100 chars get 17% more engagement per multiple studies |
| Instagram caption | 138–150 chars (feed); 2,000+ (carousels) | 2,200 | Feed posts benefit from brevity; carousels and educational content can go long |
| LinkedIn post | 1,200–1,500 characters | 3,000 | Truncates at ~210 chars; posts need a strong hook before the fold |
| Facebook post | 40–80 words (~250–500 chars) | 63,206 | Shortest posts get the most engagement; the limit is absurdly high |
| TikTok caption | 50–100 characters | 2,200 | Most viewers don't read long captions; the video does the talking |
| YouTube title | 60–70 characters | 100 | Truncates in search results around 60-70 chars depending on device |
| YouTube description | First 150 chars matter most | 5,000 | Only the first ~150 chars show above "Show more" |
| Pinterest description | 100–200 characters | 500 | Keyword-driven; front-load searchable terms |
| Threads | 100–200 characters | 500 | Short, conversational posts perform best on a text-first platform |
| Bluesky | 200–250 characters | 300 | Tight limit encourages concise writing; fill most of it |
| Reddit title | 100–120 characters | 300 | Descriptive but scannable; Redditors skip vague titles |
| Blog post | 1,500–2,500 words | No hard limit | SEO-driven; Google tends to rank in-depth content higher for informational queries |
Twitter / X: 71–100 characters
Twitter's 280-character limit replaced the original 140 in 2017, but shorter tweets still outperform longer ones. Research from Buddy Media (now Salesforce Social Studio) found that tweets under 100 characters receive 17% more engagement than longer ones. The reason is simple: short tweets are faster to read in a fast-moving feed, and they leave room for people to add their own commentary when retweeting.
The sweet spot is 71-100 characters — long enough to say something specific, short enough to be consumed at a glance. If you're going past 200 characters, you're writing a LinkedIn post in the wrong box.
Use the character counter to check your tweet length before posting. Every character counts when the limit is 280.
Instagram caption: 138–150 characters (or 2,000+ for carousels)
Instagram captions can hold 2,200 characters, but the platform truncates them after about three lines in the feed. That means the first 138-150 characters are what people actually see before tapping "more."
For standard feed posts — a single photo or a quick Reel — keep the caption short. Get the hook and the call to action into the visible portion. Hashtags can go at the end or in a comment.
The exception is carousel posts and educational content. Instagram's algorithm rewards time-on-post, and a long, useful caption on a carousel keeps people swiping and reading. In that format, 2,000+ characters is not only fine — it's strategic. The length signals depth, and the carousel format gives people a reason to stick around.
LinkedIn post: 1,200–1,500 characters
LinkedIn's 3,000-character limit is generous, but the platform truncates posts at roughly 210 characters on desktop (fewer on mobile). Everything after that hides behind "...see more." This makes the opening line the most important sentence you write.
The engagement sweet spot is 1,200-1,500 characters — about 200-250 words. That's long enough to tell a story or make a point with substance, short enough to not lose people who are scrolling during a work break.
Structure matters as much as length. Use line breaks aggressively. Bold a key phrase with the LinkedIn text formatter. One idea per paragraph. LinkedIn rewards readable formatting almost as much as the content itself.
Posts over 2,000 characters can still perform well if the content is genuinely useful — personal stories and frameworks tend to hold attention even at length. But a 3,000-character wall of text with no line breaks will get scrolled past.
Facebook post: 40–80 words
Facebook technically allows posts up to 63,206 characters — enough for a novella. Nobody should write a novella as a Facebook post.
The data is consistent: shorter Facebook posts get more engagement. BuzzSumo's analysis of over 800 million Facebook posts found that posts under 50 words got the most engagement. Other studies put the range at 40-80 words. The reason: Facebook is a casual, scroll-heavy platform. People process posts in seconds, not minutes.
For business pages, the drop-off is even sharper. A 40-word post with a strong image or link preview outperforms a 200-word post almost every time.
TikTok caption: 50–100 characters
TikTok expanded its caption limit to 2,200 characters, matching Instagram. Most creators don't need anywhere near that. The video is the content. The caption is metadata — it tells the algorithm what the video is about and gives viewers a reason to watch.
Keep TikTok captions to 50-100 characters: a hook, a keyword or two, and maybe a hashtag. The exception is educational or storytelling content where a longer caption adds context the video doesn't cover. But even then, keep it under 300 characters.
YouTube title: 60–70 characters
YouTube allows titles up to 100 characters, but search results and suggested video thumbnails truncate them. On desktop, titles cut off around 70 characters. On mobile, it's closer to 60.
The practical advice: put the most important words in the first 60 characters. Front-load the keyword. Don't save the topic for the end of the title — viewers may never see it.
Good: "How to Format Text on LinkedIn (Bold, Italic, Lists)" — 53 characters, keyword-first. Bad: "The Ultimate Complete Definitive Guide to Text Formatting on LinkedIn" — 71 characters, the actual topic is buried.
