Paste up to 50,000 characters (about 8,000 words) to see an AI probability estimate and a section-by-section view of which parts look AI-generated. Free, with no login or account. The result is an estimate, not proof of authorship.
Enter at least 50 characters and select Analyze Text.
The Detec AI detector (also written DetecAI) is a free AI content detector. You don't need an account to use it. Paste your text and it estimates how closely the passage resembles writing patterns commonly associated with AI-generated text, including drafts from tools like ChatGPT, Claude and Gemini.
It gives you an AI probability score as a percentage, plus a breakdown of how many sections look more AI-like and how many look more human-like. Results are estimates, so use them as one input alongside the writer's drafts, sources and context.
Many free AI detectors cap each check at around a thousand words. The Detec AI detector accepts up to 50,000 characters in one scan, roughly 8,000 words. That is enough for a full essay, a long blog post, a report or a chapter, so you don't have to split a document into pieces and add the scores up yourself. Very long texts can take longer to analyze.
Longer samples also give more reliable signals than a few sentences. If you only have a short paragraph, treat the result with extra caution.
Instead of giving one score for the whole document, the detector splits your text into sections and scores each one. The pattern view highlights sections as more AI-like or more human-like, so you can see where the signal comes from.
This helps with mixed documents, such as an essay with a generated introduction, or a blog post where only the summary was drafted with AI. Hover over a highlighted section to see its confidence and AI probability.
Students can check their own essays to understand how a draft may read to an automated tool. Teachers and editors can use the score as a starting point for review, not as a verdict. For anything that affects a grade, job or reputation, look at drafts, citations and revision history, and give the writer a chance to explain how the work was produced.
Bloggers and website owners can check articles before publishing. Editors can review freelance submissions and decide which sections need a closer read, a rewrite or a conversation with the author. If a draft needs smoothing, you can edit it with our free AI humanizer and then check it again.
Formal, technical, translated or heavily edited writing can look predictable to a detector, even when a person wrote it. A high score is not proof that AI was used. If your own writing is flagged, keep your drafts and revision history, and see the factors that can affect the result below.
The score estimates how closely the submitted passage resembles writing patterns the model associates with AI-generated text.
It does not identify an author, reveal which model may have been used, or determine whether the use of AI was permitted. A high or low score should not be treated as a final conclusion.
Read the passage yourself and examine its claims, sources, examples, and consistency. For important decisions, review drafts, revision history, notes, and earlier writing samples.
Give the writer an opportunity to explain the work. Automated analysis is most useful as a starting point for review, not as a substitute for evidence or conversation.
Writing detectors analyze patterns rather than the actual writing process. Several ordinary types of content can therefore be difficult to classify.
A small sample contains fewer sentence and vocabulary patterns, so its score may be less stable.
Academic, legal, technical, and corporate writing often uses consistent structures and standardized language.
Translation tools can make sentence structure more uniform even when the original passage was written by a person.
Grammar tools, templates, and heavy revision can change the patterns found in an otherwise human-written draft.
A document may combine human writing, AI-assisted text, quotations, and reusable templates.
Subject-specific terms and repeated definitions can make legitimate writing appear more predictable.
Use this process when a detection result could influence an academic, editorial, or professional decision.
Use a complete passage and note whether it is formal, translated, technical, or heavily edited.
Look for unsupported claims, invented citations, sudden style changes, and missing subject knowledge.
Examine drafts, notes, citations, timestamps, version history, and earlier work.
Ask the person to explain the argument, sources, examples, and revision process.
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Answers about the free AI detector and how to read its results.
Learn how Detec AI describes its purpose, limitations, and responsible-use principles.
About Detec AIRead practical material about AI writing patterns, false positives, editing, and human review.
Read the guidesImprove clarity and sentence flow in AI-assisted drafts, then review the result for accuracy and disclosure.
Open the free AI humanizer