The platforms and their actual limits
These numbers come from the platforms themselves and reflect the current state as of early 2026. Platform limits change occasionally, so treat this as a reference point rather than a permanent specification.
X (formerly Twitter) — 280 characters for most accounts. Verified subscribers to X Premium can post up to 25,000 characters in long-form posts. URLs always count as 23 characters regardless of their actual length, which is a quirk of the platform's URL shortening.
Instagram — Captions can be up to 2,200 characters. However, only the first 125 characters appear before the "more" cut-off in most feed views on mobile. Hashtags count toward the caption limit, and you can add up to 30 hashtags per post. Instagram Stories text overlays have much shorter practical limits depending on text size and placement.
LinkedIn — Status updates allow up to 3,000 characters. LinkedIn articles (the long-form publishing feature) allow 125,000 characters. Post titles in articles are limited to 220 characters. Comments allow 1,250 characters.
Facebook — Personal posts have a practical limit of around 63,000 characters, which is high enough that almost no one runs into it. Group and Page posts have the same generous limit. Comments are capped at 8,000 characters.
YouTube — Video titles: 100 characters, though search results typically truncate to about 60-70, so front-load your important keywords. Descriptions: 5,000 characters. Comments: 10,000 characters.
TikTok — Video descriptions: 2,200 characters. Comments: 150 characters, which is genuinely tight.
Reddit — Post titles are 300 characters. Post body text in text posts can be up to 40,000 characters. Comments can go up to 10,000 characters per reply.
Why these specific limits?
Twitter's original 140-character limit came from SMS message length (160 characters, minus 20 for the username). SMS was the primary distribution mechanism in the early days. When the platform shifted away from SMS, the limit could have changed, but by then the format had become part of the product's identity. The 2017 expansion to 280 characters was controversial for exactly this reason.
Instagram's 2,200-character caption limit is largely a spam prevention measure. Extremely long captions stuffed with hashtags and keywords are a common pattern for low-quality or automated accounts. The 125-character preview is a separate UX decision—the platform found that people scroll past long captions without reading them, so showing a short snippet and requiring a tap to expand actually increases engagement with captions that are read voluntarily.
LinkedIn's more generous 3,000-character limit reflects its professional context. Longer, more substantive posts tend to perform well on the platform because the audience expects depth. A 280-character hot take that works on X often looks shallow on LinkedIn.
What the limits mean in practice
The most useful thing to understand is that the visible character limit and the effective character limit are often different. On X, you have 280 characters on paper, but posts beyond about 200 characters see reduced engagement in most studies. The format rewards brevity more than the limit technically requires.
Instagram is almost the opposite. The 2,200-character limit suggests you can write a lot, but most of that text is hidden. The first 125 characters need to either stand alone as a complete, engaging thought, or create enough curiosity that someone taps "more." Burying your most compelling sentence in paragraph three doesn't work well on Instagram.
For LinkedIn, the platform's algorithm rewards content that keeps people reading and engaging. Long posts that are genuinely interesting tend to outperform short posts, but genuinely interesting is doing a lot of work in that sentence. A long post that meanders or doesn't deliver on its opening loses readers quickly, and drop-off signals to the algorithm that the content wasn't valuable.
A practical approach for each platform
Rather than giving you a formula, I'll share what actually works based on what consistent content creators tend to do differently from people who struggle with each platform.
On X, the best approach is usually a single clear observation or question. Trying to explain something complicated in one X post almost always produces something that's either too compressed to be useful or too long to be engaging. If you need more than 280 characters to say what you mean, X might not be the right medium for that specific thought.
Instagram captions reward either extreme: a very short caption that doesn't try to do too much, or a long caption that tells a genuine story. The mid-length caption of 200-400 words often gets skipped entirely because it's long enough to require effort but not compelling enough to justify the tap. Whatever you write, make your first line count.
LinkedIn posts that perform well usually follow a format where the first one or two lines are provocative or specific enough to stop a person mid-scroll, the middle delivers the actual substance, and the end either asks a direct question or makes a clear point worth sharing. The format is almost its own genre at this point, which is both useful and slightly depressing.
Counting characters before you post
If you're writing content for platforms with tight limits and want to count characters without dealing with the platform's sometimes finicky editor, a basic text tool does the job. Our text tools page includes a character counter that works instantly and doesn't require you to paste your copy into a social media draft just to check the length.
For X posts specifically, remember that links always count as 23 characters regardless of their actual length—this is worth knowing before you spend time trimming words to make space for a URL that ends up being shorter than you expected.
The broader point about constraints
Character limits force decisions. When you can write everything you think about a topic, you often do, and the result is a formless wall of text. A hard limit forces you to decide what's actually important in what you're trying to say. Some of the best writing in the world has come from format constraints—the haiku, the sonnet, the business memo. The limit isn't the enemy of good writing; it's often the thing that makes writing better.
That doesn't mean every platform's specific limit is wise or well-chosen. TikTok's 150-character comment limit in particular seems designed to prevent anything more substantive than a reaction. But working within whatever limits exist is a real skill, and the first step is simply knowing what those limits are.