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AIDetector365

Online AI Detector with Sentence-Level Highlights

Paste any essay, article, or message and AIDetector365 will estimate how likely it is to be AI-generated, highlight the sentences that look most machine-written, and explain why.

Runs 100% in your browser • Free • No Login

0 words · 0 / 15,000 characters

How to use the AI Detector

  1. 1Paste at least 80 words of text into the editor, or upload a TXT, DOCX or PDF file.
  2. 2Click Analyze Text. The analysis runs in your browser, so your text never leaves your device.
  3. 3Review the overall verdict, the AI probability, and the highlighted sentences.
  4. 4Read the explanations and use them as one input — not a final judgement.

What the AI detector looks for

AI-generated writing tends to share recognizable traits: very even sentence length, predictable word choices, generic transitions such as “Moreover” and “In conclusion,” balanced but non-committal arguments, and an absence of concrete personal detail.

Human writing is usually burstier. It mixes long and short sentences, takes positions, includes specific memories, names, numbers, and small imperfections. Our engine weighs these signals across the whole text and sentence by sentence.

How to read your results

The verdict summarizes the overall picture: Likely AI-generated, Mixed signals, or Likely human-written. The AI probability is an estimate, and the confidence level tells you how strong the evidence is. Short texts, heavily edited drafts and formulaic genres (legal, technical, lists) lower confidence.

No AI detector is 100% accurate. Results are probabilistic estimates and should never be used as the only evidence that someone used AI. Treat them as one signal alongside drafts, revision history, and a conversation with the writer.

Sentence-level results, explained

Instead of a single number, the detector labels each sentence as likely AI, mixed or likely human, and gives a short reason for every label. This makes it easier to see whether a whole document follows AI-style patterns or only a few passages — for example, an introduction drafted with a chatbot and a body written by hand.

Alongside the sentence view you get the overall verdict, the AI probability, a confidence level, the main AI and human indicators found in the text, and a list of limitations that apply to this particular analysis.

Why confidence matters as much as the score

The confidence level reflects how strong the evidence is, not how accurate the tool is. It is deliberately conservative: short samples, formal or templated genres and conflicting signals all lower it, and nothing in the process can raise it above what the evidence supports.

A high AI probability with low confidence should be read as “inconclusive.” A clear result with high confidence is still only an estimate and should be weighed together with drafts, writing history and a conversation with the author.

What affects the result

Length is the biggest factor: 80 words is the minimum, and 300 words or more gives the engine much more to work with. Heavy editing, paraphrasing tools, translation and mixing human and AI text all reduce the signal. Writing by non-native English speakers and highly formal prose can look AI-like even when it is entirely human.

Frequently asked questions

Is the AI detector really free?

Yes. Every tool on AIDetector365 is free with no account, no sign-up and no paid tier.

Can it detect ChatGPT, Claude and Gemini?

The detector looks for patterns shared by modern large language models, including ChatGPT, Claude and Gemini. Heavily edited or paraphrased AI text is harder to detect.

How accurate is it?

No AI detector is 100% accurate. Results are probabilistic estimates and should never be used as the only evidence that someone used AI. Treat them as one signal alongside drafts, revision history, and a conversation with the writer.

Do you store my text?

No. The detector runs entirely in your browser. Your text is never uploaded to a server.

What file types can I upload?

TXT, DOCX and PDF. The text is extracted and analyzed in your browser; the file is never uploaded.

What is the maximum length?

Up to 15,000 characters per check, which is roughly 2,000–2,500 words.

Does it work with text from Google Docs or Word?

Yes. Paste it directly, or download the document as DOCX, PDF or TXT and upload the file.

Complete guide

Perplexity and Burstiness Explained: How AI Detectors Score Text

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