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Thread Splitter

Paste a long text and get a ready-to-post thread: every post stays under the character limit of X, Threads, Bluesky or Mastodon, breaks at the end of a sentence where possible, and gets 1/n numbering. Copy the posts one by one as you publish.

Your long text 0 characters

Platform

Numbering

Position

Add 🧵 to the first post Start each paragraph in a new post No numbering when it fits in one post

How to use the Thread Splitter

Paste your long text into the box. Blank lines are treated as paragraph breaks.
Choose the platform (X, Threads, Bluesky, Mastodon) or set a custom character limit.
Pick a numbering style such as 1/5 at the end, and optionally add a thread emoji to the first post.
Review the posts: each card shows its character count against the limit.
Copy each post in order as you publish your thread, or copy or download the whole thread.

Character limits by platform

Platform	Limit per post	How it is counted here
X (Twitter), standard account	280	Weighted: links = 23, emoji and CJK characters = 2, most other characters = 1
Threads	500	Each visible character (grapheme) = 1
Bluesky	300	Each visible character (grapheme) = 1
Mastodon (default server setting)	500	Links = 23, other characters = 1; some servers allow more

Platforms change their limits from time to time and paid tiers may allow longer posts; use the custom limit for anything else, such as a server with a 1,000-character limit.

How the splitting works

The text is divided into paragraphs at blank lines, then into sentences.
Whole sentences are added to the current post while the post, including its numbering, stays within the limit. Paragraph breaks are kept inside a post as a blank line.
A sentence that is longer than one post is broken between words. Only a single word or link longer than the whole limit is cut in the middle.
Because the numbering for post 10/12 needs more room than 1/9, the tool re-splits until the number of posts and the space reserved for numbering agree.

Tips for a thread people finish reading

Lead with the payoff. The first post decides whether anyone opens the thread: state the result or promise a specific number of points.
One idea per post. Turn on Start each paragraph in a new post and write one paragraph per idea for a clean structure.
Keep sentences short. Short sentences split cleanly and read faster on a phone.
End with a summary or a question to invite replies.

Frequently asked questions

What are the character limits for X, Threads, Bluesky and Mastodon?

A standard X (Twitter) post allows 280 characters, Threads allows 500, Bluesky allows 300 and most Mastodon servers allow 500, although some servers set a different limit. Paid X accounts can post longer texts, but threads of short posts are usually easier to read.

How does the splitter decide where to break?

It fills each post with as many whole sentences as fit. If a single sentence is longer than the limit, it breaks between words, and only a single word longer than the whole limit (such as a very long link) is cut. Blank lines are kept inside a post when the next paragraph fits.

Is the numbering included in the character count?

Yes. The space for the numbering, such as ' 12/12', and for the optional thread emoji is reserved in every post, so the posts stay within the limit after numbering is added.

How does X count characters?

X uses weighted counting: most Latin letters, digits and punctuation count as 1, while emoji and characters such as Chinese, Japanese and Korean count as 2. Every link counts as 23 characters no matter how long it is, because X shortens links. The X preset follows these rules; the other presets count each visible character as 1.

Should I number my thread?

Numbering such as 1/5 tells readers how long the thread is and keeps the order clear when posts are shared on their own. It costs a few characters per post. Choose None for a more conversational style.

Does this tool post to my account?

No. It never connects to any social network and needs no login. It only prepares the text: you copy each post and publish it yourself. Your text stays in your browser.

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