The reply length checker
X gives every reply 280 characters. The limit is the easy part — the harder question is whether the draft you just wrote is readable on a phone, whether it is one reply or a thread wearing a reply's clothes, and where the sentence that loses the reader is hiding. Paste the draft below and the checker reports all of it without sending your text anywhere.
Paste a draft to check it.
What the counter is actually measuring
Two documented X limits sit behind this page. X's how to post instructions specify composing a message of up to 280 characters, which is the limit a reply shares with a standard post. The same help centre's About X Premium page documents longer posts as a subscriber feature, up to 25,000 characters.
| What you are writing | Documented limit | What this checker does with it |
|---|---|---|
| Reply to someone else's post | 280 characters (standard post limit) | Counts your draft against 280 and reports the overflow in characters |
| Your own post | 280 characters, or up to 25,000 with a Premium subscription | Same count; the 280 boundary is the one to design against if you want the post to read like a post |
| Thread of replies | No official length, but each entry still stops at 280 | Reports how many 280-character parts your text would need |
Two honest caveats. The counter measures the characters in your draft, the way your keyboard types them; X's composer applies its own rules to some input and wraps links through its own shortener, so treat the number as a strong guide rather than a byte-for-byte guarantee. And no character counter can tell you whether a reply is worth sending — for that, grade the draft with the reply quality checklist after it fits.
The three numbers that decide whether a reply lands
Character count is a hard limit. The other two numbers in the report are soft ones, and they are usually the reason a technically valid reply reads badly:
| Metric | Healthy band | When it is out of band |
|---|---|---|
| Characters | Under 280, and under 200 if you want it read at a glance | Over 280 splits into a thread; near 280 usually means one clause too many |
| Average sentence length | 12–20 words | Over 25 words means the reply reads as a paragraph, not a reply |
| Longest sentence | Under 30 words | The one sentence readers skip — usually a caveat bolted onto the main clause |
The reading-grade line is a sanity check rather than a target. A reply that grades at university level is not automatically good; on a phone, in a timeline, simpler almost always wins. If the grade is high and the character count is fine, look for a sentence carrying three ideas at once and split or cut it.
When a long reply should have been its own post
The most useful output on this page is the “replies needed at 280” line, because it answers a question people rarely ask themselves: am I replying, or am I publishing underneath somebody else's post? A draft that needs two or three parts is, functionally, its own post. Writing it as a reply to a big account costs you the byline, the notification, and the reach — and it makes the original author's thread carry your argument. Writing it as your own post with a link or a reply back to the original keeps both. The pacing side of that decision lives in the reply limits breakdown, and the strategy side in how to get more replies on X.
How to use the report
- Check the verdict first. If it says the draft fits one reply, stop optimizing length and start reading it for substance.
- Cut, do not rewrite, when you are over. The sentence that explains your explanation is almost always the one to remove.
- Watch the longest sentence. If it carries two ideas, split it — you will usually recover characters at the same time.
- Notice the mention and hashtag counts. A reply with three hashtags and two @-mentions is reading as promotion, not conversation.
- Re-run after every edit. The report updates as you type, which makes trimming a two-second loop instead of a rewrite.
Four free tools: check the length, grade the reply, plan the cadence, or generate the angle.