Thread splitter for X, Threads, and Bluesky
Paste the long version once. Get it back as numbered parts that fit X's 280, Threads' 500, or Bluesky's 300 characters, split at paragraphs and sentences so every part reads whole, with a live preview of the stack.
The live preview appears once you paste some text.
Same counting rules as posthell's composer: on X every link counts as 23 characters, on Bluesky emoji count once. Schedule the whole thread instead of pasting it part by part.
How the splitter decides where to break
- Paragraph breaks are honored first: if you separated two ideas with a blank line, they never end up glued into one part.
- Inside a paragraph it breaks at sentence boundaries, and only falls back to breaking between words when a single sentence is longer than the whole limit.
- Links are never cut in half, and on X each one is counted as 23 characters, exactly what t.co wrapping costs you.
- With numbering on, space for the n/m marker is reserved before splitting, so no part goes over once the number is added.
Frequently asked questions
How do I split a long post into a thread?
Paste the full text into the box above and pick a network. The splitter breaks it into parts that fit the network's limit, preferring paragraph breaks first, then sentence boundaries, so each part reads as a complete thought instead of a chopped fragment. Copy each part, or copy the whole thread at once.
How does X count characters in a thread?
Each post in the thread gets its own 280-character budget, and X counts every URL as exactly 23 characters because it wraps links through t.co. This splitter applies both rules, so a part that fits here fits on X.
Does the part numbering count against the character limit?
Yes. Numbering like 2/7 is normal text, so it uses part of each post's budget. When numbering is on, the splitter reserves space for it before splitting, which is why the visible text per part is slightly shorter.
What are the thread limits on Threads and Bluesky?
Threads allows 500 characters per post and supports native threads. Bluesky allows 300 characters per post, counted in graphemes (an emoji counts once), and long posts are published as a reply chain.
Can I publish the thread automatically instead of pasting each part?
Yes. posthell's composer has a native thread builder: write the parts, reorder them, attach media per part, and schedule the whole thread to publish at once. This free splitter uses the same counting rules as that composer.
Splitting is the easy half. Posting 7 parts by hand is the chore.
posthell's composer builds real threads: reorder parts, attach media to each one, and schedule the whole thing to publish at once, on X, Threads, and 13 other networks.