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Ahrefs AI Content Detector
Free no-signup AI content detector for short text, part of Ahrefs' free SEO writing tools.
AI Detectors from USD 0.00
AI detectors
22 detectors, plus 3 tools that sell a detector alongside something else. 20 publish an accuracy figure; we record it as the vendor's claim, because that is what it is.
What a detector result is worth
Every detector here produces false positives on genuine human writing. Non-native English, formulaic technical prose and heavily edited text all raise scores. None of the published accuracy figures has been independently audited, and vendors test on data they chose.
A detection result is a reason to ask a question. It is not evidence of misconduct, and no reasonable process treats it as proof on its own.
The panel we test against
Every hands-on review runs the same three test texts through these 6 detectors, before and after humanizing, on one date.
GPTZeroOriginality.aiCopyleaksWinston AISaplingZeroGPT
All detectors
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Copyleaks AI Content Detector
Enterprise AI and plagiarism detection in one report, with LMS integrations and 30+ language support.
AI Detectors from USD 13.99
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Crossplag AI Content Detector
Free English-only AI content detector offered alongside Crossplag's cross-language plagiarism checker.
AI Detectors from USD 0.00
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Decopy AI Detector
Free no-login AI detector handling up to 200,000 characters with shareable online or PDF reports.
AI Detectors from USD 9.99
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Detecting-AI
Free AI detector taking 15,000 characters per scan without signup, plus detector and humanizer APIs.
AI Detectors from USD 7.00
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Grammarly AI Detector
Free AI detector from Grammarly returning a percentage AI score, with a Pro agent for flagged phrases.
AI Detectors from USD 12.00
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Isgen
Multilingual AI detector with sentence-level highlighting, bulk scanning and an academic-priced plan.
AI Detectors from USD 8.00
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Originality.ai
AI detection plus plagiarism, fact and readability checks aimed at web publishers and content agencies.
AI Detectors from USD 12.95
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Pangram Labs
Research-led AI text detector for schools and platforms, with a free daily quota and a usage-based API.
AI Detectors from USD 20.00
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QuillBot AI Detector
Free AI detector inside QuillBot's writing suite, with sentence highlights and a 1,200-word free scan.
AI Detectors from USD 8.33
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Sapling AI Content Detector
Free AI content detector with sentence-level scores, a Chrome extension and a metered developer API.
AI Detectors from USD 12.00
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Scribbr AI Detector
Free student-facing AI detector with paragraph-level feedback and a paid premium GPT-4-capable tier.
AI Detectors from USD 19.95
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Undetectable.ai AI Detector
Free no-signup detector that aggregates results from several third-party AI detection models at once.
AI Detectors from USD 5.00
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Walter Writes AI Detector
AI detector bundled with Walter Writes' humanizer, scoring text on perplexity, burstiness and flow.
AI Detectors from USD 8.00
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Winston AI
AI text, image and deepfake detection with plagiarism checking and site certification for publishers.
AI Detectors from USD 10.00
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GPTZero
AI text detector for educators and publishers with sentence-level highlighting and batch file scanning.
AI Detectors Freemium
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Turnitin AI Writing Detection
Institution-only AI writing indicator built into Turnitin's similarity reports and LMS integrations.
AI Detectors Paid
Established API New
ZeroGPT
Free web AI text detector with highlighted sentences, plus paraphraser, summarizer and API plans.
AI Detectors Freemium
Listed New
Compilatio AI Detector
AI text detection for schools and writers, sold within Compilatio's Magister+ and Studium products.
AI Detectors Paid
Listed API New
Hive AI-Generated Content Detection
Enterprise moderation APIs that classify text, image, video and audio as AI-generated with confidence scores.
AI Detectors Paid
Listed New
JustDone AI Detector
AI detector in JustDone's student toolkit, publishing its own error rate and estimating Turnitin scores.
AI Detectors Freemium
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Smodin AI Content Detector
AI content detector inside Smodin's writing suite, covering 100+ languages with file upload support.
AI Detectors Freemium
Tools that also detect
Several vendors sell both the humanizer and the detector. Worth knowing when you compare their numbers.
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Undetectable AI
Rewrites AI-generated text into human-style output and includes a built-in AI detector.
AI Humanizers from USD 9.99
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QuillBot
Paraphrasing suite with multiple rewrite modes, grammar checker, summarizer and AI humanizer.
Paraphrasers & Rewriters from USD 8.33
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Smodin
Text rewriter, AI writer, plagiarism checker and humanizer aimed at students and researchers.
Paraphrasers & Rewriters Freemium