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Thread splitter for X (Twitter)

Most splitters cut your text to 280 and then add “1/7” — pushing every part over the limit they just measured against.

parts

Runs in your browser. Nothing you type leaves this page.

What a splitter has to get right

The numbering is part of the budget

“ 1/7” is four characters. “ 10/12” is six. “ 100/128” is eight. A splitter that fills each part to 280 and appends the counter afterwards produces parts that are 284 or 286 long, and you find out when the third one fails to send. The numbering has to be reserved before the split, and reserved at its widest — a thread that grows past nine parts widens every suffix in it.

A link is atomic and costs 23

X replaces every URL with a t.co link of fixed length, so a link costs 23 wherever it sits. It also must never be cut in half: half a link is not a link, it is noise with a full stop in it.

An emoji is one character to a reader and several to a computer

A four-person family emoji is four people joined by three invisible characters, and JavaScript’s .length reports 11 for it. Split at the wrong offset and you emit half a family plus a dangling joiner, which renders as a broken glyph. This tool splits on grapheme boundaries, so an emoji is kept whole or moved to the next part.

Sentences beat character counts

Given a choice of break points inside the budget, the last sentence end reads better than the last space, and the last space reads better than the exact limit. Nobody notices a good split; everybody notices a part that ends mid-word.

This splitter, inside the composer

The tool above is the same code that runs in PostSiete Lens, a free Chrome extension that splits threads and shows the real character count inside X, LinkedIn, Instagram, Threads and Facebook while you type. No account, no trial. It reads — it never posts for you.

Add to Chrome — free →

Questions

Why is my part shorter than 280?

Because the numbering was reserved from it, and because the split preferred a sentence end over filling the last few characters. Both are deliberate.

Can I turn the numbering off?

Yes — the checkbox above. With it off the full 280 is available to text, and nothing is appended.

Does it count links properly?

Yes. Every URL costs a flat 23 on X regardless of its written length, and links are never split across parts.

Is anything I type sent to a server?

No. The splitting runs in your browser; the page makes no network request with your text.

Sources