I run into character limits constantly when managing content across platforms. You craft a post for LinkedIn, realise it works for Twitter too, paste it in, and half your message gets cut off. Or you write an Instagram caption assuming it is unlimited, only to discover the hard cap when your carefully structured post loses its final call to action. Knowing the exact limits before you write saves time and prevents these problems.
I built the character counter partly because I got tired of pasting text into platform editors just to see if it fit. Here is a reference guide to the current limits across every major platform, along with practical advice on writing within them.
Twitter / X
Standard posts: 280 characters. Premium subscribers: 25,000 characters. Replies follow the same limits as regular posts. Direct messages allow up to 10,000 characters. Display names can be 50 characters and usernames cap at 15.
The 280 character limit forces a specific writing discipline. Every word needs to earn its place. I find it helps to write the tweet at full length first, then cut ruthlessly. Remove adverbs. Replace phrases with shorter synonyms. Cut the setup and start with the point. If you cannot say it in 280 characters, it might be better as a thread where each tweet stands alone with its own complete thought.
URLs count toward the limit, but Twitter wraps all links to 23 characters regardless of the actual URL length. Hashtags and mentions count fully. One mistake I see often is people cramming hashtags into the character limit when moving them to a reply would keep the main tweet cleaner and more readable.
Posts: 63,206 characters. Comments: 8,000 characters. Ad primary text: 125 characters recommended, 500 visible before truncation. Page descriptions: 255 characters. Event descriptions: 64,000 characters. Messenger: 20,000 characters.
Facebook technically allows very long posts, but the platform truncates anything over about 477 characters behind a "See more" link. That truncation point is your real limit for engagement. Everything above the fold needs to hook the reader. The rest is for people who clicked through, and a surprising number do if the opening is strong enough.
For ads, the 125 character recommendation exists because Facebook's own research shows engagement drops sharply on longer ad copy. That said, some niches perform better with long-form ad text. Test both, but make sure the first 125 characters contain your value proposition and call to action.
Captions: 2,200 characters. Bio: 150 characters. Comments: 2,200 characters. Hashtags: 30 per post, 10 per story. Reels captions: 2,200 characters. Alt text: 100 characters.
Instagram captions truncate after about 125 characters in the feed, with a "more" link to expand. This means your opening line is doing most of the work. I write Instagram captions by nailing the first sentence, then expanding below the fold for anyone who wants the full story.
The 30 hashtag limit is generous but using all 30 can look spammy. Research from Later and Hootsuite suggests 3 to 5 highly relevant hashtags perform as well as or better than 30 generic ones. Quality beats quantity for hashtag strategy, same as it does for content.
Posts: 3,000 characters. Articles: 125,000 characters. Comments: 1,250 characters. Company page descriptions: 2,000 characters. Headlines: 220 characters. Connection messages: 300 characters. InMail: 200 character subject, 1,900 character body.
LinkedIn truncates posts after approximately 140 characters with a "see more" link. This makes LinkedIn perhaps the most aggressive platform for demanding a strong opening line. I have seen posts with brilliant insights buried in paragraph three that nobody read because the first line was generic. Lead with your strongest point or a provocative question.
The 300 character connection message limit is painfully short. It is barely enough for a greeting, context, and reason for connecting. Every character matters here because this is often a first impression. Cut the pleasantries and get to the point: who you are, why you are connecting, and what shared interest or value you bring.
TikTok
Video descriptions: 2,200 characters. Comments: 150 characters. Bio: 80 characters. Usernames: 24 characters.
TikTok descriptions have grown from the original 150 characters to 2,200, reflecting the platform's move toward searchability and SEO. Longer descriptions with relevant keywords help your videos appear in search results. But the visual nature of TikTok means most viewers never read the description at all. Use it for searchability, not for explaining the video.
The 150 character comment limit keeps discussion fast and informal, which matches TikTok's culture. Comments here are reactions, not essays.
YouTube
Video titles: 100 characters. Descriptions: 5,000 characters. Comments: 10,000 characters. Channel descriptions: 1,000 characters. Playlist titles: 150 characters.
YouTube titles should stay under 60 characters for full visibility in search results and recommendations. The platform allows 100 but anything beyond 60 gets truncated in most display contexts. Front-load your title with keywords since the end may not be visible.
Video descriptions are underused by most creators. The first 150 characters appear in search results, so treat them like a meta description. Below that, include timestamps, links, and keyword-rich summaries of the video content. YouTube's algorithm reads descriptions when determining what a video is about, so detailed descriptions directly improve discoverability.
Pin titles: 100 characters. Pin descriptions: 500 characters. Board names: 50 characters. Board descriptions: 500 characters. Profile bio: 160 characters.
Pinterest is a search engine disguised as a social platform. Descriptions here are not for human readers primarily, they are for Pinterest's search algorithm. Include specific keywords that describe the content of your pin. "Easy 30-minute pasta recipe with roasted tomatoes" performs better than "Delicious dinner idea" because it contains the exact terms people search for on the platform.
Writing Within Limits
The practical advice comes down to three principles I follow when writing for any platform with character limits. First, write without limits, then cut. It is easier to trim a complete thought than to expand a truncated one. Second, front-load every piece of text. The most important information goes first because truncation is the default on almost every platform. Third, use a character counter while writing, not after. Checking your count as you draft prevents the frustrating experience of crafting a perfect post only to discover it is 30 characters over the limit.
Platforms change their limits periodically. Twitter's expansion to 280 characters, Instagram's increase from 30 to 2,200 caption characters, and TikTok's description expansion all happened without much warning. I update this reference when limits change, but always verify against the platform's current interface if the exact count matters for your use case.