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About this tool
Count em dashes, smart quotes, triads and other punctuation tells in a draft, with rates per 1,000 words and rewrite suggestions.
The Em Dash AI Tell Checker counts the punctuation and structure habits that stand out in unedited language-model prose — em dashes (U+2014), curly quotes, the ellipsis glyph, semicolons, sentence-initial connectives such as Moreover and Ultimately, rule-of-three lists, and "not only... but also" framing — and reports each as a rate per 1,000 words. It also measures sentence- and paragraph-length variation using the coefficient of variation, since evenly sized sentences are one of the clearest signs a draft has not been read aloud. Every flag threshold is shown and adjustable, so you can see why a passage was marked.
Open Em Dash AI Tell Checker on AltFTool — it loads instantly in your browser.
Provide your input — an image, text, or data.
Let the tool analyze or generate the result.
Review, refine, and reuse the output wherever you need it.
Each flag comes with the surrounding sentence, so you can jump straight to the fix.
Per-1,000-word rates let you compare a 400-word post with a 4,000-word feature.
Replace every em dash with a comma, full stop or bracket and copy the cleaned draft.
This tool flags a draft above 3 em dashes per 1,000 words by default, and you can change that number. There is no official limit — the em dash is correct punctuation — but because it is not on a standard phone or laptop keyboard, several of them in short web copy is worth a second look.
An em dash (—, U+2014) marks a break in a sentence; an en dash (–, U+2013) joins ranges such as 10–15; a hyphen (-) joins words such as well-known. Mixing a spaced en dash and an em dash in the same document usually means the text was assembled from two sources, which is why this tool flags that combination.
No. The score counts style conventions, and there is no reliable way to detect authorship from text alone — published AI-detection classifiers produce both false positives and false negatives, especially for non-native English writers. Use the result to improve the draft, never to accuse anyone.
It is the coefficient of variation: the standard deviation of words per sentence divided by the mean. A value under 0.4 means nearly every sentence is the same length, which is what makes a passage feel flat; mixing a five-word sentence with a thirty-word one raises the number and the readability.