AI CONTENT DETECTOR Sentence-level scoring Free · No signup to start

AI Content Detector

Instantly check whether text was written by AI — ChatGPT, Claude, Gemini, GPT-5 and more — scored sentence by sentence. Free. No signup to start.

AI Content Detector FREE
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3 free checks a day · no signup · your text is never stored

📝 Sentence-level analysis Multi-model · ChatGPT, Claude, Gemini 🔒 Privacy-first · text never stored Transparent methodology GDPR compliant
Privacy-first

Your text is processed to return a result and is never stored or used to train models.

Transparent methodology

We publish how the score is produced and its limits. Read the methodology →

Free to start

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An honest note on accuracy. AI detection is probabilistic, not proof. Our detector performs strongly on internal benchmarks with a low false-positive rate, but it can be wrong — especially on short text, heavily edited drafts, or writing by non-native English speakers. We show the evidence behind every score so you can make an informed judgment. Use TextSight to support human review, never as the sole basis for a decision.
Coverage

Detect AI Content From Every Major Model

TextSight is a multi-model AI content detector. It learns the patterns each model family leaves behind, so it works across the current frontier of AI writing — not just one vendor.

OpenAI
ChatGPT · GPT-5 · GPT-4o · GPT-4
Anthropic
Claude Opus 4.8 · Sonnet 4.6 · Haiku
Google
Gemini 3 Pro · Gemini 2.5 · Flash
xAI
Grok 4 · Grok 3
DeepSeek
DeepSeek V3 · R1 · and newer
Meta
Llama 4 · Llama 3.3
Mistral
Mistral Large · Mixtral
Microsoft
Copilot · plus fine-tuned variants

Because the underlying signals are model-agnostic — predictability, sentence rhythm, lexical variety and structure — newer and unreleased models still produce a useful estimate. The detector is updated as the landscape changes.

How it works

How the AI Detector Works — 3 Simple Steps

No setup, no card. Paste your text into the AI detector and read the sentence-level breakdown in seconds.

1 PASTE

Drop in your text

Paste a paragraph or a full document up to 5,000 characters into the detector above. As an AI text detector, TextSight handles short snippets and full essays alike.

2 ANALYZE

The model scores it

Multiple language signals — perplexity, burstiness, and stylometry — combine into one probability. Our AI content detection methodology runs five classifiers on every sentence, not just statistical guessing.

3 READ

See the evidence

Get an AI probability score plus the human-likelihood complement, and judge the result for yourself. This AI detection tool covers all major language models and is updated as new models ship.

What you get

Sentence-Level AI Detection With Visible Confidence Scores

Not just a number — the signals and detail behind every verdict. Our AI content detector reads perplexity, burstiness, and stylometry, and shows why text is flagged, sentence by sentence.

Sentence-level detail

See which passages drive the score instead of guessing from a single overall percentage.

Clear 0–100 score

One AI probability number from the AI content checker, with the human-likelihood complement, so the result is easy to read.

Privacy by default

Text is processed to return your result, then discarded. Never stored, never used for training.

Every major model

Recognizes patterns from ChatGPT, GPT-5, Claude, Gemini, DeepSeek, Grok and Llama — updated as new models ship.

Published methodology

We document how the score is produced and where it can fall short. Read it →

Low false positives

Tuned to keep human writing from being wrongly flagged — and we tell you when confidence is low.

Why it matters

Why Run Text Through An AI Content Detector?

AI writing is now everywhere — and for a lot of work, knowing whether a person actually wrote something still matters.

Generative AI can produce a fluent essay, article or report in seconds. That is genuinely useful, but it also means a polished piece of text no longer guarantees a human sat down and thought it through. For anyone who relies on the authorship of a document — a teacher grading an assignment, an editor approving a guest post, a recruiter reading a cover letter, a brand paying for original copy — that uncertainty has a real cost.

An AI content detector closes part of that gap. It does not replace judgment, and it cannot prove who wrote a sentence. What it does is give you a fast, evidence-backed second opinion: an AI-probability score, the specific sentences that look machine-written, and the signals behind the call. That is enough to know where to look more closely, start a fair conversation, or ask for a draft history — instead of guessing.

Used this way, detection protects the things people actually care about: academic fairness, editorial trust, original work that gets paid for, and writing that genuinely reflects the person who signed it. The goal is never to punish AI use — plenty of good writing is AI-assisted — but to keep authorship honest where it counts.

It is also a quick habit. A check takes seconds, runs free on this page, and gives you something concrete to point to — which is far better than a vague feeling that a piece "reads like AI." Whether you are reviewing one assignment or a queue of freelance submissions, a fast, repeatable check keeps your standards consistent and your review fair to everyone.

Under the hood

How The Multi-Model Detector Scores Your Text

One number, many signals. Here is what the AI checker actually measures before it returns a result.

Human writing carries a particular unevenness. The pace shifts, sentence lengths vary, and word choices occasionally surprise. Large language models are trained to predict the most probable next word, which makes their output smoother and more statistically "average" than what people usually write. The detector measures that difference across several dimensions at once.

It reads perplexity — how predictable each word is given the words around it; burstiness — how much sentence length and rhythm vary across a passage; lexical variety — the range of vocabulary and how often certain favored AI phrasings appear; and structure — whether sentences cluster around the same few templates. Crucially, it does this sentence by sentence, not just once for the whole document, so a single AI paragraph buried in human writing still shows up.

Because no model family writes the same way, the detector is multi-model: it weighs patterns characteristic of ChatGPT, Claude, Gemini and the rest, then combines them into one probability rather than betting on a single classifier. The signals are model-agnostic, so a model released after today still produces a useful estimate. The full breakdown — every sentence, the likely source family and a downloadable report — is available in the app. See the published methodology →

Reading your result

What The AI Score Means

Writing is rarely all-or-nothing. The detector places your text on a spectrum and tells you which of four states best fits — with the sentence-level evidence behind it.

!

Likely AI-generated

High AI probability across most sentences — the text closely matches patterns produced by large language models.

~

AI-generated & edited

Mostly AI with human touch-ups. Some sentences read as reworked, but the underlying draft looks machine-written.

~

Human-written & AI-assisted

Mostly human, with passages that look AI-assisted — common when a writer uses AI for part of a draft.

Likely human-written

Low AI probability with the natural irregularity of human writing — varied rhythm and word choice throughout.

Common question

AI Detector vs Plagiarism Checker

They answer different questions, and most teams use both — one checks originality, the other checks authorship.

AI content detector

Looks at how the text was written. It estimates whether a machine generated the wording, even when every sentence is original and appears nowhere else online.

  • Flags AI-generated phrasing and structure
  • Works on brand-new, never-published text
  • Scores each sentence, not just the document
  • Answers: "Was this written by a person?"

Plagiarism checker

Looks at where the text came from. It compares your writing against billions of published sources to find copied or closely matched passages.

  • Flags text that matches existing sources
  • Needs a source to exist to find a match
  • Reports a similarity percentage and citations
  • Answers: "Is this copied from somewhere?"

A document can be 0% plagiarized yet fully AI-generated — original wording, no human author. That gap is exactly why an AI content detector matters alongside a plagiarism checker.

How we compare

TextSight vs Other AI Detectors

An honest look at where TextSight fits. We show the evidence behind every score and stay genuinely usable for free.

FeatureTextSightTypical free detectorEnterprise detector
Free, no signup to startYesOftenNo
Sentence-level highlightingYesParagraph onlyYes
Signals shown behind the scoreYesRarelySometimes
Multi-model coverageYesVariesYes
Published methodologyYesNoYes
Honest "not proof" framingYesRarelyVaries
Usable free word limitGenerousTightPaywalled

No detector is a lie detector. The right one shows its work — that is the bar TextSight holds itself to. See the 2026 AI detector comparison →

Accuracy & limits

An Honest Word On Accuracy

AI detection is probabilistic, not proof. On our internal benchmarks the detector performs strongly with a low false-positive rate, and it is most reliable on longer passages of unedited text written in English. We deliberately do not publish a single headline accuracy number, because the honest answer depends on the text in front of you.

Detection is hardest on three kinds of writing: very short passages, where there is not enough signal to score reliably; heavily edited or paraphrased text, where human revision blurs the patterns; and formal or non-native English writing, which can legitimately resemble AI. A widely cited 2023 Stanford study found that several popular detectors wrongly flagged more than half of essays written by non-native English speakers as AI-generated — a reminder that a score is a starting point, not a verdict.

That is why every TextSight result comes with a sentence-level breakdown and the signals behind it, and why we say plainly: use the detector to support a human decision, never as the sole basis for one. For grading, hiring or publishing, pair the score with drafts, version history and a conversation with the writer. Read our full methodology →

Our position

Built For Integrity, Not Evasion

TextSight is a verification tool. It exists to help people check authorship and protect trust — not to defeat anyone's review.

We are deliberate about what this product is for. The AI content detector is built to support honest review: to give educators, editors, recruiters and content teams clear, explainable evidence they can act on, alongside their own judgment. Every result is framed as a probability with the reasoning attached, never as a guilty verdict, precisely so it is used fairly.

We do not position detection as a weapon, and we are equally clear that no detector should be the sole basis for a high-stakes decision about a person. When a score is borderline, the right next step is a human one — review the drafts, look at the version history, and talk to the writer. That is how authorship questions get resolved fairly, and it is the workflow this tool is designed to support.

Who uses it

The AI Checker Built For Writers, Editors & Agencies

A fast second opinion before you publish, grade or approve — with the sentence-level evidence to back up a fair, human-led call. Wherever authorship matters, an AI content check is a quick, low-effort safeguard.

Educators

Get sentence-level evidence from the AI checker to support a fair, human-led academic-integrity review.

Editors & publishers

Add an AI-content check to your editorial QA before content goes live. The AI content checker shows which sentences read as AI-generated, not just an overall score.

Writers

Check your own drafts with the AI detector before you publish, so you can confidently say your work is your own.

Content teams

Verify supplier or freelance copy meets your originality standards before you pay. Whether you're auditing one essay or running bulk scans, our AI detection tool scales with you.

FAQ

AI Detector FAQ

How accurate is the AI content detector?
It performs strongly on our internal benchmark with a low false-positive rate, but no AI detector is perfect — results are most reliable on longer, unedited text. Every verdict comes with a sentence-level breakdown and the signals behind the score, so you can weigh the evidence rather than trust a single percentage. Use it to support human review, not as sole proof of authorship.
Is the AI checker free, and do I need to sign up?
You can run checks on this page free, with no signup and no credit card, on up to 5,000 characters per scan. A free account unlocks the full sentence-by-sentence report, the likely source model and a downloadable report, plus more scans per day.
Which AI models can it detect?
It estimates AI likelihood for text from ChatGPT (GPT-5, GPT-4o), Claude Opus 4.8 and Sonnet 4.6, Gemini, DeepSeek, Grok, Llama, Mistral and other large language models. The signals are model-agnostic, so newer or unreleased models still produce a useful estimate.
Can it detect ChatGPT-generated content?
Yes. ChatGPT is the most common source we see, and the detector is tuned to recognize its phrasing and structure across GPT-5, GPT-4o and GPT-4. You get an AI-probability score plus the sentences that read most like ChatGPT output. Treat the result as strong evidence to review, not absolute proof.
Can it detect Claude, Gemini, Grok and other models?
Yes. The detector is multi-model — it weighs patterns from Claude (Opus 4.8, Sonnet 4.6), Gemini, Grok, DeepSeek, Llama and Mistral, not just ChatGPT. Because the signals are model-agnostic, content from newer or unreleased models still produces a useful estimate.
Does it store or train on my text?
No. Text you submit is processed to return your result and is then discarded. It is never stored and never used to train our models. See our Privacy Policy for full detail.
Can it detect paraphrased or mixed AI-and-human text?
It scores text sentence by sentence, so a mixed document shows which specific lines read as AI-generated versus human. Heavily edited or paraphrased writing is inherently ambiguous, so treat a low score as evidence to review — not proof a human wrote it.
Can it detect AI in essays and academic papers?
Yes — long-form writing like essays is where detection works best, because there is more text to analyze. That said, formal academic prose can legitimately resemble AI, so a high score should begin a fair, human-led review (drafts, version history, a conversation with the writer), never end one.
Will Turnitin or my school's checker agree with this result?
Not always. Different detectors use different models and thresholds, so scores can vary between tools — including school systems like Turnitin. Use TextSight as an independent second opinion, with the sentence-level evidence behind it, rather than a guarantee of what another checker will report.
Does it work for languages other than English?
The detector is trained and tuned for English, which is where it is most reliable. You can paste text in other languages, but treat non-English results as directional rather than definitive.
Learn more

AI Detection, Explained

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Sentence-level analysis · Privacy-first, never stored · Transparent methodology