AI Content Detector

Free AI Detection Utility

AI Content Detector

This AI content detector checks whether a piece of writing was likely produced by a model like ChatGPT, Gemini, or Claude, or written by a person. Paste in plain text, Markdown, or HTML and you'll get an AI-likelihood percentage, a built-in readability score, and a breakdown of eight writing signals - with the exact sentences that triggered each flag highlighted directly in your own copy.

8-Signal Detection
Cliches, structure, dashes, rhythm & more
Sentence-Level Flagging
See exactly which sentences triggered it
Text, Markdown, or HTML
Both are detected and stripped automatically

Your Text

30 - 5,000 words · text, Markdown, or HTML
0 / 5,000 words · 0 characters 10 of 10 checks left today
HTML tags and Markdown syntax (#, **, lists) are detected automatically and stripped before analysis - no need to clean the input first.

AI Likelihood Score

Waiting for input
Your AI-likelihood score will appear here once you click Check for AI Content.
0 % AI-Likely
-

0%Human-Like
0%Sentences Flagged
0Words
0Sentences

What This AI Content Detector Does, and Who It's For

You give it one input - a passage of text, or Markdown or HTML you paste straight from a CMS, document, or AI tool - and it produces an AI-likelihood score built from eight separate, named writing signals, a readability score, and a highlighted copy of your text showing exactly which sentences contributed to that score. It doesn't check facts, grammar, or originality; it looks specifically at whether the writing style resembles typical AI output.

Who actually uses this
Editors screening submitted drafts, agencies checking freelance or AI-assisted copy before it goes to a client, students reviewing their own writing before submission, and SEO teams deciding whether an AI-drafted page needs another editing pass all reach for the same kind of tool, for the same reason: they want a fast, explainable second opinion, not a black-box verdict.
What sets this detector apart
Most AI detectors return one number from a proprietary model with no explanation attached. This one works the other way around: every point of the score traces back to a signal you can see, and every flagged sentence is highlighted in your own text with a reason attached - closer to how a human editor would mark up a draft than to a pass/fail machine verdict.

How to Use the AI Content Detector

  1. 1
    Paste your text or HTML
    At least 30 words, up to 5,000. Plain text works, and so does Markdown or raw HTML source copied straight from a CMS, Google Docs, Word, or an AI tool's own output - markup and syntax are detected and stripped automatically.
  2. 2
    Click Check for AI Content
    Complete the quick verification if asked. The analysis runs on AudEsto's own servers - your text is never sent to a third-party AI API.
  3. 3
    Read the score and breakdown
    The headline percentage blends an eight-signal document score with the share of individual sentences flagged. Open the breakdown to see which signals moved the needle, and check the readability panel alongside it.
  4. 4
    Review the highlighted sentences
    Scroll to the highlighted copy and hover any flagged sentence to see exactly what triggered it, then revise - or leave it as-is if the flag doesn't actually apply to your writing style.

How the Detection Works

Every request runs two layers of analysis, computed locally with no external AI model involved. First, eight document-level signals are scored and combined into a base result. Second, each individual sentence is classified on its own, similar in approach to how sentence- or span-level flagging works in commercial tools such as Copyleaks - rather than only averaging the whole document into one blended number.

AI cliche phrase density - 25% weight
Counts how often the text uses stock AI transitions and filler phrases - "in today's digital age," "it's important to note," "delve into," and around 70 others - relative to its length. Reliable, but easy for a prompted AI to avoid.
Structural formula - 22% weight
Heavy list/heading density combined with "Step N" sequences and repeated "for example / consider / suppose" illustrative framing used to ground otherwise-generic advice with invented specifics. This is what catches AI writing that's been explicitly told to avoid stock phrases - it doesn't depend on any specific wording at all. List density alone is deliberately given very little weight here, since plenty of genuine human writing (READMEs, recipes, tutorials) is list-heavy too; it's the illustrative-example habit paired with structure that's the real tell.
AI punctuation tells - 15% weight
Genuine em-dashes and en-dashes, plus colon-introduced lists ("Here's what matters: speed, cost, quality"). Most people never type a real em-dash, but current AI writing tools reach for one often.
Sentence-length burstiness & repetitive openers - 24% combined weight
Human writing naturally mixes short and long sentences and varies how sentences begin. Generic AI output tends toward more uniform sentence length and repeatedly reaches for the same transition words ("Moreover," "Additionally,") to start sentences.
Lexical predictability, vocabulary diversity & passive voice - 14% combined weight
How much of the text is built from roughly 150 of the most common English words, a length-adjusted vocabulary-diversity index, and a passive-voice count - three minor, supporting signals rather than deciding factors on their own.
Why cliche and structural signals aren't simply averaged in
Cliche-stuffed AI text and heavily-structured "framework" AI text are two largely independent styles - a document rarely scores high on both at once. Averaging every signal together let one strong mode get diluted by the other's absence, understating clearly AI-patterned text. So the stronger of the two "modes" carries most of the weight, with the weaker one still contributing a smaller nudge rather than being averaged away.

What Your Results Mean

Four numbers matter, and they answer different questions - the overall percentage is an estimate, not a certainty:

ScoreLabelWhat it suggests
0 - 15%Likely Human-WrittenNatural writing traits across most or all signals.
16 - 35%Mostly Human, Some AI TraitsMostly natural, with a few patterns that also show up in AI text.
36 - 55%Mixed / UncertainRoughly even mix of signals - treat as inconclusive.
56 - 75%Likely AI-GeneratedSeveral strong AI-writing patterns found together.
76 - 100%Very Likely AI-GeneratedDense AI-style patterns across most or all signals at once.
"Sentences Flagged" percentage
Separate from the headline score - this is the share of individual sentences that independently tripped a flag, the same "how much of this document looks AI-written" framing commercial detectors use. A high overall score with a low flagged percentage usually means one or two signals are doing most of the work; a high flagged percentage means the pattern runs through the whole document.
Readability score
A completely separate question, shown in the same panel so you don't have to run a second tool: how easy is this text to read, on a 0-100 scale built from six published formulas (Flesch-Kincaid, Gunning Fog, SMOG, Coleman-Liau, and more - the same engine behind AudEsto's Content Readability Checker). AI-likelihood and readability don't move together - text can be easy to read and still score as likely AI, or difficult to read and still score as likely human.

A Real Example

A short passage stuffed with stock AI phrasing and uniform sentence length:

Input:
"In today's digital age, it is important to note that content marketing plays a crucial role in business growth. Moreover, businesses must delve into the world of SEO. Furthermore, they should navigate the complexities of search algorithms. Additionally, a robust content strategy is essential."
Result:
A score in the low 60s ("Likely AI-Generated"), with 4 of the 5 sentences individually flagged. Cliche density and repetitive openers score at or near the maximum; sentence-length variety scores low, since every sentence runs roughly the same length.
What it means:
Not proof this exact text came from an AI model - a description of its style. Swapping the stock phrasing for plainer language, varying sentence length, and mixing up how sentences open would lower the score regardless of who or what wrote the original draft.

AI Content and SEO: What Actually Matters

Google has said plainly that it rewards content based on quality and helpfulness, not on how it was produced - there's no blanket ranking penalty for using AI. Where the risk actually sits is narrower, and worth separating into three different things rather than treating every AI-writing pattern as a ranking factor.

Direct ranking factor: no
Whether text "sounds AI-written" is not something Google's ranking systems score directly. There is no public AI-detection signal built into search ranking.
Indirect effect: sometimes
Heavy cliche density and uniform structure often travel with unedited, low-effort content - and that combination tends to read poorly and convert badly on its own merits, independent of anything AI-related.
The real risk: scaled, unedited publishing
Google's spam policies target content - AI-generated or not - published at scale primarily to manipulate rankings, not to help a reader. A high score here is a useful diagnostic signal that a page may need another editing pass; it is not, by itself, evidence of a policy violation.

Who Actually Uses an AI Content Detector

  • Content editors: screen freelance or AI-assisted drafts for heavy AI-style patterns before they're scheduled to publish.
  • SEO and content teams: decide whether an AI-drafted page needs a deeper human editing pass before it goes live, using the score as a prioritization signal.
  • Writers: self-check a draft after using AI for a first pass, to see which specific sentences still read as generic rather than guessing.
  • Agencies: spot-check delivered copy against a brief that requires original, human-edited writing, then discuss flagged sections with the writer.
  • Educators: get a fast, explainable starting point for a conversation about submitted work - never used alone as proof.

Common Mistakes When Reading Results

  • Treating any single score as proof. No AI detector, including this one, should be the sole basis for an accusation about someone's writing.
  • Checking a very short excerpt. Under roughly 100 words, the burstiness and vocabulary signals don't have enough material to be meaningful.
  • Ignoring writing context. Formal, technical, or non-native-English writing can score higher than it should - always read the highlighted sentences before drawing a conclusion.
  • Comparing scores across different detectors. Every tool weighs different signals - percentages from one detector aren't directly comparable to another's.

Expert Recommendations: Editing AI-Assisted Text

  • Replace stock transitions ("moreover," "in today's world," "delve into") with plainer, more specific language tied to the actual topic.
  • Mix short, direct sentences with longer ones instead of keeping every sentence the same length.
  • Vary how sentences begin instead of repeatedly reaching for the same transition word.
  • Add concrete, specific detail - numbers, examples, a real anecdote - that a generic first draft tends to skip.
  • Read it out loud. Phrasing that sounds stiff spoken aloud is usually the same phrasing that scores highest here.

Related Concepts

AI content detector vs. plagiarism checker
A plagiarism checker compares your text against published sources to find matching passages. This tool never compares against anything external - it only looks at your text's own writing style. Text can be fully original and still score high here, or copied and still score low.
AI content detector vs. readability checker
A readability checker (like AudEsto's own tool, whose scoring engine this page reuses for its readability panel) measures how easy text is to read. It says nothing about whether the writing sounds AI-generated - the two scores are independent and shown together here for convenience, not because one predicts the other.
AI content detector vs. grammar checker
A grammar checker flags spelling and grammatical errors. This tool ignores correctness entirely - grammatically flawless text can still score as highly AI-like if it's stylistically uniform and cliche-heavy.

Limitations and Important Considerations

  • This is a heuristic, not a forensic tool. No AI content detector on the market, including this one, can prove authorship with certainty. Treat every result as a signal to investigate, never as final proof.
  • False positives happen. Non-native English writers, very formal writing styles, and technical or legal writing can score higher than expected because they share surface patterns with AI output.
  • False negatives happen too. Heavily edited or rewritten AI text can score low, since editing removes many of the surface patterns this tool looks for.
  • Short text is less reliable. Under roughly 100 words, several signals - especially sentence-length variety - don't have enough material to be meaningful.
  • Free daily limit. The tool has a daily allowance shown in the rate-limit badge above the input box; it resets once per day.

Frequently Asked Questions

An AI content detector is a tool that analyzes a piece of writing and estimates how likely it is to have come from an AI model such as ChatGPT, Gemini, or Claude rather than a person. It looks at writing patterns - phrasing habits, sentence rhythm, punctuation, word choice - that tend to differ between typical human writing and typical AI output, then returns a likelihood score and a breakdown of what it found, rather than a flat yes/no verdict.

It scores your text against eight independent signals - AI cliche phrase density, a structural-formula signal (list/step density and repeated "for example" style framing, which catches AI writing that's been told to avoid cliches), sentence-length variety, repetitive sentence openers, punctuation habits like em-dashes and colon-led lists, word predictability, vocabulary diversity, and passive voice - then blends that with a sentence-by-sentence classification, similar in spirit to how commercial detectors like Copyleaks flag individual spans rather than scoring a whole document as one block. Every signal is visible in the results panel, and every flagged sentence is highlighted in your own text with the reason attached.

Yes. It's free with a daily usage allowance and no account, email, or credit card required. If you go over the daily free limit, it resets the next day.

No AI content detector, including this one, is 100% accurate, and none should be treated as proof on their own. This tool uses transparent, rule-based signals rather than a trained black-box classifier, so you can see exactly why a score came out the way it did - but it's still an estimate based on writing patterns, not a verified fact. Heavily edited AI text can score low, and unusual human writing can score higher than it should.

Yes, and this is a documented limitation across every AI detector on the market, not just this one. Very formal writing, technical or legal documents, and non-native-English writing can share surface patterns with AI output - like more uniform sentence length or common transition words - and score higher than they should. Never treat a detector score as the sole basis for accusing someone of using AI.

Yes, both. Paste raw HTML source, formatted content copied from a CMS or Word, or Markdown (the "# heading", "**bold**", bullet/numbered-list syntax many editors and AI tools output) - the tool detects either format automatically, strips the markup, and gives every heading and list item its own sentence boundary before analysis. There's no need to clean the input first, and list/heading structure is itself one of the detection signals.

They're separate questions answered together in one panel. The AI-likelihood score estimates whether the writing style resembles AI output; the readability score (built from six established formulas) estimates how easy the same text is to read, regardless of who or what wrote it. A piece of writing can score low on AI-likelihood and still be hard to read, or score high on AI-likelihood and still be easy to read - checking both at once saves re-running a separate tool.

Google has stated it rewards content based on quality and helpfulness, not on how it was produced, and has no blanket penalty for AI-assisted writing. What its spam policies do act against is content - AI-generated or not - published at scale primarily to manipulate rankings rather than help the reader. In practice, that makes thin, unedited, mass-produced content the real risk, not AI assistance by itself.

No. Your text is analyzed in memory for that one request, and the result goes straight back to your browser - nothing is saved to a database or shared anywhere on AudEsto's side. The analysis also never leaves AudEsto's own servers; unlike some AI writing tools, no part of your text is sent to a third-party AI API.

A plagiarism checker compares your text against published sources to find matching or near-matching passages. An AI content detector doesn't compare against anything external - it only looks at the stylistic patterns inside your own text to estimate whether it reads like typical AI output. Text can be entirely original and still score high on an AI detector, and text can be copied and still score low - they answer two different questions.

This AI content detector is one of several free writing and SEO utilities AudEsto runs alongside its full white-label site audit. If you're already reviewing content quality before publishing, it's a natural moment to check the rest of the page too - browse all free SEO optimization tools, or try the AI Content Detector above and run a complete audit next.