Three different horizontal lines, three different jobs, and one of them is a dead giveaway for AI writing. Here is how to tell them apart and when to strip each.
The three dashes
- Hyphen ( - ) is the short one. It joins words (well-known, two-thirds) and breaks words across lines. You type it with the key next to zero.
- En dash ( – ) is medium length, about the width of an "n." Its main job is ranges and connections:
2010–2020,pages 5–10,the London–Paris route. - Em dash ( — ) is the long one, about the width of an "m." It sets off a clause or an aside, like a stronger comma or parentheses.
Why this matters for AI text
Chatbots overuse the em dash. They scatter spaced em dashes through prose to set off asides, far more often than the average person typing would. That density is the most recognizable AI writing tell, which is why removing em dashes is the single highest-impact change when you want text to read as human.
The en dash matters here too, because cleaners and find-and-replace passes often miss it. You strip the em dashes, the text looks better, but stray en dashes are left behind, still signaling machine-edited content.
When to remove them
- Em dash: usually remove from AI text. Replace with a comma when it sets off an aside, a period or semicolon when it joins two complete thoughts, or delete it for trailing emphasis.
- En dash in a real range (
2010–2020): keep it, or convert it to a hyphen for plain-text and code contexts where the en dash looks out of place. Either reads fine. - En dash used like an em dash: treat it like an em dash and replace it.
The fast way to handle both
A cleaner that understands dashes does this in one pass: it converts em dashes to your chosen replacement, handles stray en dashes the same way, and keeps number ranges readable as hyphens. textscrubr lets you pick comma, hyphen, or removal, and it catches the en dash that manual find-and-replace leaves behind.
Should you ever keep an em dash?
In your own polished prose, the em dash is a legitimate, useful piece of punctuation. The goal is not to ban it forever. It is to remove the unnatural density that signals a chatbot wrote the draft, so an occasional intentional one is fine, a flurry of them is the tell.