Copyleaks claims over 99% accuracy for its AI detector, but a flag is an estimate rather than proof. Copyleaks itself warns that text edited with tools like Grammarly can be flagged as potential AI content.
A flag from the Copyleaks AI detector is a statistical estimate rather than definitive proof of academic dishonesty. While Copyleaks reports high accuracy figures, teachers must treat every detection percentage as a signal to review revision histories and talk with students rather than as an automatic finding of misconduct.
Copyleaks claims that its detection engine delivers over 99% accuracy backed by independent third-party studies. For its latest detection model, Copyleaks publishes language-specific accuracy rates, including 99.97% for human English text and 99.20% for AI English text. In Spanish, Copyleaks reports 99.85% accuracy on human writing and 98.02% on AI-generated text. Copyleaks also claims low false-positive rates when evaluating submissions written by non-native English speakers. These figures are Copyleaks's own claims.
No automated detection engine can prove conclusively how a document was created. Short passages provide too few statistical signals for an algorithm to separate human cadence from machine output reliably. Mixed text, such as an AI-drafted outline pasted into a student's own prose, is harder to classify. A high probability score tells an instructor where statistical anomalies exist in the writing style. It does not establish intent or verify the exact writing process. For a broader examination of algorithmic reliability across vendors, see our guide on are AI detectors accurate.
The web version of the Copyleaks AI detector lets anyone paste text to receive an immediate probability score. Users can scan up to 25,000 characters without creating an account or signing into a profile. The resulting output displays an overall percentage indicating how much of the submitted passage appears to be machine-generated text. Copyleaks states that its engine detects output produced by major large language models, including ChatGPT, Gemini, Claude, and related tools across more than 30 languages.
Beyond basic percentage scores, Copyleaks offers a paid diagnostic feature called AI Logic. This feature breaks down the diagnostic reasoning behind a flagged submission by displaying two specific analytical categories:
In addition to identifying machine-generated text, Copyleaks operates a traditional plagiarism scanner. Copyleaks can check AI and plagiarism in one report that flags copied internet sources alongside suspected generative text. For schools evaluating options across multiple platforms, our review of Turnitin alternatives for teachers highlights how different services combine these scanning workflows.
Copyleaks itself warns that assistive writing software can trigger AI flags. Copyleaks notes that platforms like Grammarly use generative artificial intelligence (AI) for core features, meaning that human-written essays edited with these assistants can be flagged as potential AI content. That warning matters for teachers who encourage students to use spell-check and grammar tools during revisions.
Copyleaks does not say on its AI detector page how much editing it takes to trigger a flag. An authentic student essay that underwent thorough digital proofreading may return an elevated probability score. Teachers who penalize students based solely on raw percentage scores risk punishing learners for using standard editing aids. For Grammarly's own detector, see our guide to the Grammarly AI detector.
To prevent unfair accusations, instructors must establish clear classroom boundaries regarding assistive software before assignments begin. Defining acceptable proofreading tools in an AI syllabus statement ensures students understand which digital aids are permitted on each paper. If a student submits an essay that triggers a flag after using grammar software, review the document's version history rather than issuing an academic penalty. For advice on supporting students caught in this scenario, see our guide on what to do when a learner is falsely accused of using AI.
Copyleaks structures its pricing through credit-based plans tailored for individual professionals, teams, and academic institutions. The Copyleaks pricing page also has Enterprise and Education tabs. The table below outlines the core subscription plans published on the Copyleaks pricing page.
| Plan | Price (Annual Billing) | Credits and Capacity | Included Features |
|---|---|---|---|
| Free Scan | $0 | Up to 25,000 characters per scan | Basic probability percentage, no login required |
| Personal | $13.99/month ($167.88 billed annually) | 1,200 credits (up to 300,000 words or 1,200 images) | See the Copyleaks pricing page |
| Pro | $74.99/month ($899.88 billed annually) | 12,000 credits, 25 user seats | 25 user seats |
| Education | Not captured; see the pricing page | Not captured | Not captured |
The Personal tier provides individual educators with basic credit allotments to check suspect passages across the school year. The Pro tier expands capacity for small departments or writing centers that share scanning duties across up to 25 team members. Education pricing sits on its own tab of the Copyleaks pricing page linked above, so check current school terms there. If your school already licenses Turnitin, our guide to the Turnitin AI score explains how that score is read.
Copyleaks provides several software integrations that allow instructors to scan student submissions directly within existing classroom environments. Rather than requiring teachers to copy text into a web browser manually, Copyleaks connects directly to major learning management systems (LMS). Supported LMS platforms include:
For educators who grade outside an LMS, Copyleaks publishes browser extensions for Google Chrome and Microsoft Edge, as well as an add-on for Google Docs.
If every paper is run through a detector, instructors may spend grading sessions scrutinizing probability percentages instead of engaging with student arguments. For an institutional breakdown of software alternatives, review our guide on selecting an AI detector for teachers.
A flagged paper should initiate an instructional conversation rather than an academic integrity hearing. Because detection algorithms rely on statistical predictability, an elevated score simply indicates that the text shares structural features with language model outputs. To investigate the context behind a score, follow this review sequence:
During a writing conference, ask the student to define specialized vocabulary used in the paper and explain why they organized specific paragraphs in that sequence. A student who wrote the paper can usually explain these decisions. If a student cannot, treat that as a reason for a longer conversation. You can learn more instructional verification strategies in our guide on how to catch AI without a detector.
This approach also serves students who want to know how their papers will be evaluated. When students understand that instructors assess draft histories and subject mastery rather than trusting a single score, anxiety around automated false positives can ease. For a comparison of alternative detection platforms, review our guide analyzing is GPTZero accurate and our broader report on how do teachers detect AI.
Before relying on Copyleaks for grading, run a few drafts you know were written by hand through the free 25,000-character scan, and write down how your class will handle a flag.
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Copyleaks claims its detector achieves over 99% accuracy backed by third-party studies, reporting 99.97% accuracy on human English text and 99.20% on AI-generated English text. However, detector scores remain statistical estimates rather than conclusive proof. Copyleaks itself warns that text edited with tools like Grammarly can be flagged as potential AI content, and edited or blended text is difficult for any detection model to classify with complete certainty.
Yes, Copyleaks provides a free scan on its website for up to 25,000 characters without requiring an account login. The free web scanner reports the percentage of content likely generated by AI. AI Logic, which explains why text was flagged, is a paid feature.
For individual users on annual billing, the Copyleaks Personal plan costs $13.99 per month ($167.88 billed annually) for 1,200 credits, covering up to 300,000 words or 1,200 images. The Pro plan costs $74.99 per month ($899.88 billed annually) and includes 25 user seats with 12,000 credits. Copyleaks also maintains Education and Enterprise tiers with pricing available directly through its pricing page.
Yes, Copyleaks states that its AI detector detects text produced by ChatGPT, Gemini, Claude, and other large language models across more than 30 languages. Its paid AI Logic feature explains a flag through AI Phrases and AI Source Match.