Social Media Character Limits 2026: Every Network and Field

Social media character limits run from 300 on Bluesky to 5,000 for a YouTube description. In between: 500 on Threads and on a default Mastodon server, 800 for a Pinterest description, 1,024 for a Telegram photo caption, 2,000 for a Discord message, 2,200 for an Instagram caption and 3,000 for a LinkedIn post. Facebook is the odd one out: it publishes no limit at all for an ordinary post.

The post box is only one field. A bio, a display name, a username, alt text, a video title, a hashtag list and a link each have their own cap, and they differ more than the post limits do. TikTok gives you 80 characters for a bio, Instagram 150, Bluesky 256 and a default Mastodon server 500. Documented alt text caps run from 500 characters on Pinterest to 2,000 in the Bluesky app, and mastodon.social allows 10,000.

What a network calls a character also differs, and this is where posts fail in ways that are hard to spot. Bluesky and Mastodon count what you see on screen. Threads counts an emoji by its UTF8 bytes when you post through its developer interface, so one thumbs up costs 4 of your 500. TikTok counts UTF16 units. Mastodon counts every link as 23 characters whatever its length, while the Bluesky app shortens a link before it counts it. A caption that fits on one network can be rejected on the next one for reasons that have nothing to do with how many words it has.

Below you get one cheat sheet, then a table per network with every field we could find on that network's own pages, then the rules for links, emoji, hashtags and alt text that sit across all of them. Where a network publishes no number, we say so rather than repeat a figure from another blog.

On October 28, 2026 we opened the help center or developer documentation of every network on this page and copied each limit from there. Help centers that only render in a browser (Instagram, Facebook, TikTok, Pinterest and Discord's support site) were read in a browser. The rest were fetched directly. Every limit in a table links to the page it came from, and the full list of sources sits at the bottom.

Two networks publish their limits as code rather than help articles, so we read the code. For Bluesky that is the open schema for a post record and a profile record, plus the constants file of the official Bluesky app, which sets the alt text and direct message caps. For Mastodon it is the validator that measures post length and the settings each server reports about itself. We asked mastodon.social for its live settings and three other large servers for theirs, because a Mastodon limit is a default each server can change.

We also measured how emoji count, using the grapheme rules in Unicode's text segmentation standard and plain byte counts, and we ran a long App Store link through the Bluesky app's own shortening function to see what it costs inside 300 graphemes. Those are our measurements, and the page says so where they appear.

What we left out: X, and numbers that only appear on third party blogs. Several fields people search for, such as the Threads bio or the LinkedIn headline, have no official number anywhere we looked. For those, the table says not published, and where other guides agree on a figure, we name it and mark it unconfirmed.

Five hundred characters is about 80 to 90 words of plain English. That is enough for a full thought with a link, and short enough that a list of features will not fit. If an announcement needs more, the text attachment is the tool Meta built for it: write a tight 500 character post that says what changed, then put the detail in the attachment. Keep in mind that an attachment cannot sit on a post with an image, so a product shot and a long changelog have to be two posts.

The link rule took effect on December 22, 2025. Since then the developer interface refuses a sixth link, and tools that post on your behalf have to follow it. One link per post is the habit that keeps you clear of it, and it reads better anyway.

If you schedule Threads posts from a tool, the emoji rule matters more than it seems. Ten plain emoji count as 40 through the developer interface, not 10, so a caption your editor shows at 480 characters comes out at about 510 and is rejected. Trim emoji first when a scheduled Threads post fails for length. Our guide on how to schedule Threads posts covers the scheduling side, and the Threads statistics page has the audience numbers.

Three hundred graphemes is about 50 words. That forces a choice the longer networks never ask for: what is the one thing this post says? For a product update, it is usually the change and the reason to care, in two sentences, with the link in a card. Hashtags are optional on Bluesky and the schema stores up to 8 of them outside the text, so tools can tag a post without eating the 300.

A thread of replies is the native way to say more, and each reply gets its own 300. Our guide on how to schedule Bluesky posts shows the free and paid ways to post them ahead of time, and the Bluesky statistics page covers who is reading.

This is where posting the same update to Bluesky, Threads and Mastodon gets fiddly by hand: three networks, three ways of counting, one draft. Spreadcast writes a separate caption for each network and warns you, by how many characters, when one runs over that network's limit. If the hashtags are what push it over, it drops them from the end first, and only then cuts back to the last full sentence that fits. You can try it from the start page with your App Store link or website.

For years the Instagram rule was 30 hashtags per post. The app now stops at 5, and the help page puts it plainly: more than 5 and your caption or comment will not post. The developer reference that scheduling tools rely on still says 30, which means a tool built to that number can send a caption the app would refuse. If a scheduled Instagram post fails and the caption looks fine, count the hashtags before anything else.

Five tags is enough for the job hashtags do now, which is telling Instagram what the post is about. Pick them the way you would pick search words: the category, the problem the post solves, the type of post. The social media caption generator page has example sets per network, and the Instagram post generator covers sizes and layout. For the wider strategy, see how to promote an app on Instagram.

With no hard cap, the useful number on Facebook is Meta's own advice for ads: 50 to 150 characters of primary text and a 27 character headline. Meta writes those numbers for paid placements, but the reason behind them applies to an organic post too. Feeds show the first few lines and hide the rest behind a link to read more, so the first sentence has to carry the post.

For a Page that shares product news, a good pattern is one sentence that names the change, one that says who it helps, and a link. The Facebook post generator has examples in that shape, and the social media image sizes guide covers the picture that goes with it.

Three thousand characters is roughly 450 words, longer than most readers give a post. LinkedIn's own ad guidance says text past about 150 characters gets cut off, which is why the strongest LinkedIn posts put the whole point in the first two lines and treat everything after the fold as optional detail.

For a product update, that means the change and the result in the opening line, then a short list of what is new, then the link. Long posts work when they teach something; release notes rarely need more than 600 characters. The LinkedIn post generator has examples at that length, and the LinkedIn carousel size guide covers document posts, which carry their text inside the slides.

On TikTok the caption sits on top of the video, and a long one stays folded until someone taps it. Its main jobs are search and context: the words someone would type to find the video, a hashtag or two, and one line that makes sense of what they are watching. A few hundred characters does that. The longer limits suit tutorials that spell out the steps in text.

Plan around 2,200 if a tool posts for you, because that is the limit the developer interface enforces, whatever the app itself allows. The TikTok app promotion guide has caption examples for app founders.

One hundred characters is the cap, but search results and phone screens show less than that, so the words a viewer needs go first. A title that front loads the topic ("Budget App Tutorial: Split a Bill in 30 Seconds") survives any cut. The description works the same way: the first two lines show before the fold, and the rest is space for chapters, links and credits.

The byte rule only bites if you write in a language with accented letters or paste emoji into the description, since each of those takes two to four bytes. For a channel that posts Shorts made from app updates, the YouTube MCP server guide covers uploading from Claude, with the quota and audit rules Google sets.

On Pinterest the title and description are search text first. People find Pins by typing, so the title should hold the words they would type, inside its first 40 characters, and the description should say in plain language what the Pin shows and who it is for. Eight hundred characters is room for two or three sentences and a few keywords; filling it with a list of tags reads as spam and gets you nothing.

The Pinterest pin generator has title and description examples, and Pinterest for app founders explains how Pin search works for an app.

The most common Telegram length error is a post that would fit as a message but is sent with a picture. A message can be 4,096 characters, a caption only 1,024, and the Bot API does not wrap the extra into a second message. It refuses the post.

There are two clean ways around it. Keep captions under 1,024 and put the long version in a text post, or send the picture first and the full text as a message straight after it. The second keeps the image and the words together in the channel, one above the other.

Spreadcast does the second one for you. When a Telegram caption runs past 1,024 characters, it posts the picture or video first and the full text as a message right under it, so a long channel post never fails for length. Telegram channels post from the same calendar as Instagram and the other networks; the features page lists all 11. For growing the channel itself, see how to grow a Telegram channel and how to schedule Telegram channel posts.

Threads got longer and stricter at once. In September 2025 Meta added text attachments of up to 10,000 characters on text posts, the first time Threads allowed more than 500 characters in one post. Three months later, from December 22, 2025, the developer interface started refusing posts with more than 5 links.

Instagram cut hashtags to 5 per post in the app. Its developer reference was not updated, so the 30 hashtag figure lives on in tools and in older guides.

YouTube launched title testing for creators with access to advanced features in December 2025: up to three titles per video, with the winner chosen by watch time. The 100 character title limit did not change, but there is now a direct way to find out which 100 work.

Bluesky's post schema still says 300 graphemes and 3,000 bytes. What many guides miss is how little room a link takes in the official app, which posts a shortened link in place of the full URL: in our test a 61 character App Store link cost 30 graphemes.

Mastodon's documented defaults are still 500 characters for a post and 30 for a display name, but the servers people actually use report their own numbers. mastodon.social reports a 40 character display name and a 10,000 character alt text cap, both above the documented defaults, and infosec.exchange allows 11,000 characters per post.

Here is what posting one product update to eleven networks looks like by hand. You write the long version for LinkedIn, cut it to 2,200 for Instagram and strip it to 5 hashtags, cut it again to 500 for Threads and Mastodon, again to 300 for Bluesky, check the Telegram caption against 1,024, write a separate title for YouTube and Pinterest, and then make an image for each. That is an hour of trimming for one announcement, every time you ship.

Spreadcast is marketing automation for social media, built first for App Store apps. Paste your App Store link at the start page and it builds a brand kit from the listing: icon, colors and screenshots in an iPhone frame. Businesses without an app start from a website or a short description. When a new version goes live or the app hits a ratings milestone, Spreadcast designs the post, writes a caption for each network sized to that network's limit, and publishes it, on full autopilot or after one tap of approval.

The after picture: one draft, eleven captions, each within its limit, with the image designed in your brand. Instagram gets 3 to 5 hashtags, Threads at most one topic tag, Bluesky a version under 230 characters, Telegram a channel post under 900 so it sits under the picture, and YouTube and Pinterest a separate title under 100. Nothing goes out until you approve it, if you want it that way. It publishes to Instagram, Facebook, Threads, LinkedIn, Pinterest, TikTok, YouTube, Bluesky, Mastodon, Telegram and Discord.

It also works from the AI tools you may already use. Through the Spreadcast MCP server, Claude, ChatGPT and other MCP clients can write captions per network, design posts and carousels, and schedule them. Free makes 3 posts to download with a small Spreadcast mark. Pro is $29 a month for clean posts with no cap, publishing to 10 social accounts and autopilot; a $19 Post Pack covers 10 posts designed and published, with no subscription. The details are on the pricing page.

For the pictures that go with these captions, the social media image sizes guide has every size in pixels. For writing the captions themselves, see the social media caption generator, and for App Store fields such as the subtitle and keywords, the App Store character counter. If you are planning a month of posts, the social media content calendar and how to automate social media posts are the next steps.

For measuring what the posts do once they are out, see the engagement rate calculator and the guide to social media KPIs. If your updates are app releases, the app update announcement examples show how other apps fit a release into a short post.