User Guide
Paste your full text
Write it as one continuous piece first. Composing directly into a thread tends to produce posts that each fit but do not read well in sequence.
Choose the platform
X / Twitter is 280, Bluesky 300, Threads and Mastodon 500. Choose Custom for anything else — a client with a different ceiling, or a self-imposed shorter limit.
Pick a numbering style
1/5 at the end, 1/5 at the start, or 1. at the start. The counter itself consumes characters, and the tool accounts for that when splitting.
Review where the breaks landed
The tool splits on sensible boundaries rather than mid-word, but the best threads break at the end of a thought. Adjust your text if a post ends awkwardly.
Copy each post in turn
Copy them one at a time in order, or use Copy All. Posting out of order is the most common way a thread ends up unreadable.
Front-load the first post
It is the only one most people will see. It has to work alone and give a reason to read the rest — treat it as the headline, not the introduction.
About the Thread Splitter
This tool takes a long piece of text and splits it into numbered posts that each fit a platform’s character limit, without breaking words or losing content. It runs entirely in your browser.
The limits it handles
| Platform | Limit | Notes |
|---|---|---|
| X / Twitter | 280 | The tightest of the four; paid tiers allow more |
| Bluesky | 300 | Slightly more room than X |
| Threads | 500 | Roughly a short paragraph per post |
| Mastodon | 500 | Default; individual servers can raise it |
| Custom | Any | For other clients or a self-imposed shorter limit |
One detail that trips up manual splitting: the numbering counts against the limit. Adding “12/15” to a post costs five or six characters, so a post sitting at exactly 280 no longer fits once numbered. The tool reserves that space before it splits, which is why its posts fit and hand-counted ones sometimes do not.
Numbering, and why it matters
Threads arrive out of order. Replies interleave, clients render them differently, and people land on post seven from a quote rather than post one. Numbering is what makes a thread navigable rather than a pile of fragments.
1/5 at the end keeps the opening words clean, which matters because the first line is what shows in previews. 1/5 at the start makes position obvious immediately — better for reference threads people skim. 1. at the start is the lightest option, useful when you do not want to commit to a total up front.
Writing a thread that people finish
The first post carries everything. It is the only one guaranteed to be seen, and it decides whether the rest is read. State the point rather than promising it — “a thread on X” is weaker than the actual claim.
One idea per post. The split is a natural pause. A post containing two half-ideas reads badly in a way the same sentence would not in an article.
Do not end mid-sentence. Continuation across posts is hard to follow when replies appear between them. Whole thoughts survive interleaving.
Keep it short. Completion rates drop sharply after about ten posts. If your text needs twenty, it probably wants to be an article with a link.
When a thread is the wrong format
Threads suit sequential arguments and narratives. They are poor for anything a reader needs to return to, search or share a specific part of — and platform limits change, which can strand old threads awkwardly. The X developer documentation documents the current constraints if you are building against them.
If your text is long enough to need splitting at all, consider whether one post linking to a full piece would serve readers better. Use the Character Counter to check whether it fits as a single post first.
Privacy
Everything runs in your browser. Nothing you enter is transmitted, logged or stored.
Frequently Asked Questions
Does the numbering count against the character limit?
Yes, and it is the usual reason hand-split threads fail to post. Adding “12/15” costs five or six characters. This tool reserves that space before splitting, so every post fits once numbered.
Which numbering style should I use?
1/5 at the end keeps the opening words clean, which matters for previews. 1/5 at the start makes position obvious immediately, better for reference threads. 1. at the start is lightest and avoids committing to a total.
How long should a thread be?
Under about ten posts. Completion rates fall sharply beyond that. If your text needs twenty posts, it is probably an article that wants a single post linking to it.
Will it break words in half?
No. The tool splits on sensible boundaries rather than mid-word. For the best result, write so that each post ends on a complete thought — continuation across posts is hard to follow once replies interleave.
What is the character limit on X?
280 for standard accounts, with paid tiers allowing considerably more. Bluesky is 300, and Threads and Mastodon are both 500, though individual Mastodon servers can raise theirs.
Can I use a limit that is not listed?
Yes. Choose Custom and enter any number. This is useful for third-party clients, for Mastodon servers with non-standard limits, or when you simply want shorter posts than the platform permits.
Should I post them all at once?
Post in order, replying each to the previous one. Order is what makes a thread navigable, and posting out of sequence produces a thread that reads as fragments no matter how it is numbered.
Is my draft sent anywhere?
No. The splitting happens in JavaScript inside this page, so unpublished drafts stay on your device.