Thread Splitter for X, Threads, Bluesky & Mastodon
Long text in, a numbered thread out: every post within the platform’s real limit.
Try before you buy.
- Free preview: the first posts of your thread (half of them, up to 10) in full, with the thread’s post count and longest post.
- Locked until you unlock it: download and copy.
- Unlock: Pro pass, ₹179 for 30 days or ₹79 for 1 week, a one-time payment that never renews. Unlock: Pro pass, $5.99 for 30 days or $2.99 for 1 week, a one-time payment that never renews.
Ways to unlock shows how to get the full result.
Printing this result is locked in the free preview.
Your text
A blank line starts a paragraph, where the thread prefers to break. A line with only --- always starts a new post.
Characters, from 20 to 100,000.
Thread
Your posts appear here as you type.
Locked in the free preview. Opens the ways to unlock this result.
Locked in the free preview. Batch runs unlock with a pass.
Locked in the free preview. Query results unlock with a pass.
About the Thread Splitter for X, Threads, Bluesky & Mastodon
Paste a long text and get it back as a thread whose every post fits the platform: X’s 280, Threads’ 500, Bluesky’s 300 or a Mastodon server’s 500, counted the way each platform counts, or any limit you set. Links, @mentions and hashtags are never cut, and the posts break where a reader expects a pause: after a paragraph, then a line, then a sentence. The number you add to each post (1/5, (1/5), 1/ or a 🧵 on the first post) is counted too.
All the posts are chosen together rather than one after the other, so a post is not stuffed to the limit when breaking a little earlier gives the next one a whole sentence. Edit any post and the rest of the thread flows on from it. Nothing you type leaves your browser.
Without a pass, the free preview shows the first half of the posts (up to 10) in full, with the count of every post; the whole thread, Copy and the .txt file come with a Pro pass.
How to use it
- Paste or write your text. Leave a blank line between paragraphs: the thread breaks there first.
- Choose the platform: X, Threads, Bluesky, Mastodon (type your server’s limit if it is not 500) or Custom limit.
- Pick the numbering and whether to Keep sentences whole; with it off, the thread uses the fewest posts and may break after a comma or a word.
- To force a break, put a line with only
---where the new post should start. To change one post, press Edit on it: the posts before it stay, and the rest flows on. - Copy each post, or press Copy all posts or Download .txt (with a pass, or after unlocking this thread).
Examples
Paragraph 1 (190 characters) Paragraph 2 (190 characters) Paragraph 3 (190 characters)
Post 1: paragraph 1 + " 1/3" (194 of 280) Post 2: paragraph 2 + " 2/3" (194 of 280) Post 3: paragraph 3 + " 3/3" (194 of 280)
Two paragraphs together would be 382 characters, so each gets a post. The 4 characters of " 1/3" count towards the 280.
Read the full write-up: https://example.com/blog/how-we-rebuilt-our-onboarding-flow
X: 47 of 280 (the link counts as 23) Threads: 83 of 500 (the link counts in full)
X counts every link as 23 characters whatever its length; Threads counts the whole address.
Big news today. --- Here is what changes for you.
Post 1: Big news today. 1/2 Post 2: Here is what changes for you. 2/2
Common uses
- Turning a blog post, a newsletter or meeting notes into an X or Bluesky thread.
- Posting the same long announcement on X (280), Bluesky (300) and Threads (500), each split to its own limit.
- Keeping a 1/5-style count right when the thread grows past nine or ninety-nine posts.
- Writing a Mastodon thread for a server with a 1,000- or 5,000-character limit.
How each platform counts
- X: up to 280, weighted. Every link counts as 23 whatever its length, an emoji counts as 2, and Chinese, Japanese and Korean characters count as 2 (X Developer Platform — Counting characters).
- Threads: up to 500 characters, and each emoji counts as its size in UTF-8 bytes, usually 4; at most 5 different links a post (Threads API — Posts).
- Bluesky: up to 300 characters as you see them, and at most 3,000 bytes (app.bsky.feed.post lexicon). The Bluesky app shows long links shortened (host and the start of the path, then …) and counts that short form, which is what is counted here.
- Mastodon: 500 characters on servers that keep the default; a link counts as 23 and @user@server counts as @user (Mastodon documentation — Posting to your profile). Servers may set their own limit, so type yours.
- Custom limit: characters as you see them, so an emoji or an accented letter is one.
Every limit on the page comes from the same sourced list as Social Media Character Limits.
Where the thread breaks
Each possible break gets a cost: after a paragraph costs nothing, after a line a little, after a sentence a little more, after a comma or a dash more again, and in the middle of a sentence the most. A post that is left half empty costs too, and so does every extra post. The splitter picks the set of breaks with the lowest total, the way typesetting software breaks lines into a paragraph.
A web address, an @mention, a #hashtag, an e-mail address or a $cashtag is never cut. A full stop after Mr, Dr, e.g. and other short abbreviations does not count as the end of a sentence. In Chinese, Japanese and Thai, which have no spaces, the thread breaks after a full stop such as 。 or between words as your browser finds them. A single word longer than a whole post is cut between letters, and that post says so.
Editing one post
Press Edit on a post, change it and press Apply. The posts before it stay exactly as they are, the edited post becomes a post of its own (two if it is now too long), and the rest of your text flows on from there. The breaks that keep this are written into your text as lines of ---, so they stay when you change something else; Undo edit puts the text back.
Limitations
- The platforms’ apps can change how they count. The rules here follow their published documentation and code, so leave a few characters spare on a post that is right at the limit.
- Threads and X decide on their side whether a post with many links or hashtags reaches people; the splitter only makes sure each post fits.
- Images, polls and alt text are not part of a post’s text, so they are not counted.
- Posting is up to you: the page makes the posts and never connects to your accounts.
Privacy
On this device: nothing is sent
Everything happens in your browser. What you enter or open here is not uploaded or stored by MySmartCoPilot.
Frequently asked questions
What do I get without a pass?
Without a pass, Thread Splitter for X, Threads, Bluesky & Mastodon shows the first posts of your thread (half of them, up to 10) in full, with the thread’s post count and longest post. Until you unlock it, the result can’t be downloaded or copied. A Pro, Premium or Ultimate pass, a one-time payment that never renews, unlocks the full result. The pricing page lists the passes and their prices.
How many characters can an X post have?
280, weighted: links count as 23, emoji and Chinese, Japanese and Korean characters as 2. Subscribers to X Premium can post longer texts; the splitter keeps every post within the 280 that every account has.
Does the 1/5 numbering count towards the limit?
Yes. The splitter keeps room for the number in every post, as wide as the thread’s largest number, so “10/12” fits as well as “1/12”.
Why did a post end before the limit?
Because the next sentence would not have fitted whole, and breaking it would cost more than starting a new post. Turn off Keep sentences whole to fill posts more, breaking after a comma or a word where that saves a post.
Can I decide where a post starts?
Yes: put a line with only --- (three dashes) in your text. Pressing Edit on a post and changing it adds such lines for you, so the posts before stay as they are.
Is my text uploaded?
No. The splitting and counting happen in your browser, and the page works offline once it has loaded.