# AI detectors and plagiarism checkers

Canonical HTML: https://www.prelearning.de/en/ai-content-checks/
Updated: 2026-09-04
Active entries: 22

Detector scores are indicators, not proof of authorship.

## 1. Scribbr AI Detector
- Provider: Scribbr
- Categories: ai_text_detector
- Access: free_no_account
- Inputs: text
- Languages: en
- Summary: Free web detector for pasted text. The provider states unlimited checks with a per-submission word limit and no sign-up.
- Use case: A quick additional comparison signal for English-language text.
- Caution: A percentage is not proof of authorship. Do not submit confidential or personal text without checking the current privacy terms.
- Last checked: 2026-09-04
- URL: https://www.scribbr.com/ai-detector/

## 2. QuillBot AI Detector
- Provider: QuillBot
- Categories: ai_text_detector
- Access: free_no_account
- Inputs: text
- Languages: en, de, fr, es
- Summary: Freely accessible text detector that estimates AI-generated and AI-refined passages as percentages.
- Use case: Useful for comparing a second detector on the same text.
- Caution: QuillBot itself notes that no detector is 100% reliable. Treat the result as an indicator only.
- Last checked: 2026-09-04
- URL: https://quillbot.com/ai-content-detector

## 3. GPTZero
- Provider: GPTZero
- Categories: ai_text_detector, authorship_evidence
- Access: free_limited_account_optional
- Inputs: text, document
- Languages: en
- Summary: Detector with document- and sentence-level analysis. Short scans are available directly; larger scans and extra features may require an account.
- Use case: Useful for sentence highlights and, separately, writing-process evidence features.
- Caution: GPTZero also states that AI detection is not perfect. Flags should be checked against drafts, sources and the writing process.
- Last checked: 2026-09-04
- URL: https://gptzero.me/

## 4. Copyleaks AI Detector
- Provider: Copyleaks
- Categories: ai_text_detector
- Access: free_limited_account_optional
- Inputs: text, document
- Languages: multilingual
- Summary: Multilingual AI text detector. A limited number of free checks may be available without an account; broader use is account-based.
- Use case: An additional comparison for multilingual text and mixed human/AI passages.
- Caution: Provider accuracy claims do not guarantee an individual result. Access limits and supported languages may change.
- Last checked: 2026-09-04
- URL: https://copyleaks.com/ai-detector

## 5. Sapling AI Content Detector
- Provider: Sapling
- Categories: ai_text_detector, api
- Access: free_no_account
- Inputs: text
- Languages: en
- Summary: Public web demo with an overall probability and sentence analysis; an API is also offered.
- Use case: Useful as a quick third comparison and for technically reproducible checks through an API.
- Caution: Do not treat probabilities as definitive classifications. API access and limits must be checked separately.
- Last checked: 2026-09-04
- URL: https://sapling.ai/ai-content-detector

## 6. Grammarly AI Detector
- Provider: Grammarly
- Categories: ai_text_detector, authorship_evidence
- Access: free_limited_account_optional
- Inputs: text, document
- Languages: en
- Summary: Free detector for a broad estimate; Grammarly also offers features for documenting how a text was created.
- Use case: Useful when detector signals and verifiable writing-process evidence should be considered separately.
- Caution: Grammarly states that AI detectors are not 100% accurate and should not determine authorship on their own.
- Last checked: 2026-09-04
- URL: https://www.grammarly.com/ai-detector

## 7. Originality.ai AI Detector
- Provider: Originality.ai
- Categories: ai_text_detector, plagiarism_checker, fact_checker
- Access: free_limited_premium
- Inputs: text, document, website
- Languages: multilingual
- Summary: Combines AI detection with plagiarism and other quality checks. The provider offers a few short free scans; full functionality is paid.
- Use case: Useful when AI signals and similarity searching are to be compared in one commercial tool.
- Caution: Check current storage and privacy terms before pasting unpublished work.
- Last checked: 2026-09-04
- URL: https://originality.ai/

## 8. Pangram AI Detector
- Provider: Pangram Labs
- Categories: ai_text_detector, api
- Access: free_limited_account_optional
- Inputs: text, document
- Languages: multilingual
- Summary: AI text detector with web scanning, browser extensions and an API. Free credits or limited checks are offered.
- Use case: Another independent comparison signal, especially for newer models and AI-edited text.
- Caution: Accuracy figures are largely provider claims. A single result must not be used as proof.
- Last checked: 2026-09-04
- URL: https://www.pangram.com/

## 9. Winston AI
- Provider: Winston AI
- Categories: ai_text_detector, ai_image_detector, plagiarism_checker
- Access: free_trial_account
- Inputs: text, document, image
- Languages: multilingual
- Summary: Account-based trial for AI text, image and plagiarism checks; the provider lists a time- and credit-limited free plan.
- Use case: Useful for document and image checks with a combined report.
- Caution: Free credits, duration and features may change. Results remain probabilistic.
- Last checked: 2026-09-04
- URL: https://gowinston.ai/ai-content-detector/

## 10. ZeroGPT
- Provider: ZeroGPT
- Categories: ai_text_detector, ai_image_detector, ai_video_detector, plagiarism_checker
- Access: free_limited_premium
- Inputs: text, image, video
- Languages: multilingual
- Summary: Public tool with AI text detection plus image, video and plagiarism functions; paid plans raise the limits.
- Use case: A broad feature comparison, not a sole basis for decisions.
- Caution: The platform bundles many tools. Check privacy, advertising, limits and result quality separately for each mode.
- Last checked: 2026-09-04
- URL: https://www.zerogpt.com/

## 11. Turnitin AI Writing Report
- Provider: Turnitin
- Categories: ai_text_detector, institutional
- Access: institutional
- Inputs: document
- Languages: selected_languages
- Summary: Institutional AI-writing analysis within Turnitin. Direct access normally comes through a school, university or organisation.
- Use case: Relevant when the institution uses Turnitin and its official reports need to be interpreted.
- Caution: Do not treat it as a public self-test. Observe language, minimum-length and file requirements as well as institutional rules.
- Last checked: 2026-09-04
- URL: https://www.turnitin.com/solutions/topics/ai-writing/

## 12. Scribbr Plagiarism Checker
- Provider: Scribbr
- Categories: plagiarism_checker
- Access: paid_account
- Inputs: document
- Languages: multilingual
- Summary: Paid similarity and plagiarism check for academic writing with a source report.
- Use case: For finding possible text overlap and missing citations before submission.
- Caution: Similarity is not automatically plagiarism; matches require academic and citation-based review.
- Last checked: 2026-09-04
- URL: https://www.scribbr.com/plagiarism-checker/

## 13. QuillBot Plagiarism Checker
- Provider: QuillBot
- Categories: plagiarism_checker
- Access: premium_account
- Inputs: text, document
- Languages: multilingual
- Summary: Account-based plagiarism checking in the QuillBot suite; full use is typically a Premium feature.
- Use case: An additional similarity search for drafts and citation review.
- Caution: Check privacy and storage terms before uploading unpublished work.
- Last checked: 2026-09-04
- URL: https://quillbot.com/plagiarism-checker

## 14. Copyleaks Plagiarism Checker
- Provider: Copyleaks
- Categories: plagiarism_checker, institutional, api
- Access: free_limited_account_optional
- Inputs: text, document
- Languages: multilingual
- Summary: Multilingual similarity checking with web, account, education and API options. Free use may be limited.
- Use case: Comparing source matches and institutional integrity checks.
- Caution: Check the current source corpus, free limits and storage rules before use.
- Last checked: 2026-09-04
- URL: https://copyleaks.com/plagiarism-checker

## 15. Grammarly Plagiarism Checker
- Provider: Grammarly
- Categories: plagiarism_checker, authorship_evidence
- Access: premium_account
- Inputs: text, document
- Languages: en
- Summary: Plagiarism and source checking within Grammarly products; broader use is account-based or paid.
- Use case: Useful for English writing when language review and source similarity are checked together.
- Caution: Language correction, AI detection and plagiarism checking are different functions and must not be conflated.
- Last checked: 2026-09-04
- URL: https://www.grammarly.com/plagiarism-checker

## 16. Turnitin Similarity
- Provider: Turnitin
- Categories: plagiarism_checker, institutional
- Access: institutional
- Inputs: document
- Languages: multilingual
- Summary: Institutional similarity checking normally provided through a school, university or learning platform.
- Use case: Interpreting an official Similarity Report from the user's institution.
- Caution: A similarity score is not an automatic plagiarism decision; sources, citations and permitted overlap must be reviewed.
- Last checked: 2026-09-04
- URL: https://www.turnitin.com/solutions/academic-integrity/

## 17. Quetext
- Provider: Quetext
- Categories: plagiarism_checker
- Access: free_limited_account_optional
- Inputs: text
- Languages: en
- Summary: Web-based similarity checking with limited free use and paid upgrades.
- Use case: An additional search for publicly discoverable text overlap.
- Caution: Coverage and limits differ from institutional systems; do not upload confidential text without review.
- Last checked: 2026-09-04
- URL: https://www.quetext.com/

## 18. PlagAware
- Provider: PlagAware
- Categories: plagiarism_checker
- Access: paid_account
- Inputs: text, document, website
- Languages: de, en
- Summary: Plagiarism and similarity checking focused on German-language documents and web content; use is generally paid.
- Use case: An alternative for German-language text and source reports.
- Caution: Check pricing, trial options and data processing before uploading.
- Last checked: 2026-09-04
- URL: https://www.plagaware.com/

## 19. Hive Detect
- Provider: Hive
- Categories: ai_image_detector, ai_video_detector, api
- Access: free_limited_account_optional
- Inputs: image, video, audio, api
- Languages: interface_en
- Summary: Provider tool for detecting potentially AI-generated or manipulated images and videos, with technical APIs also available.
- Use case: An additional media check for images, short videos or suspected deepfakes.
- Caution: Confidence scores are not proof of authenticity. Check rights, consent and current privacy terms before uploading media.
- Last checked: 2026-09-04
- URL: https://www.hivemoderation.com/ai-generated-content-detection

## 20. Sightengine AI Media Detection
- Provider: Sightengine
- Categories: ai_image_detector, ai_video_detector, api
- Access: free_trial_account
- Inputs: image, video, api
- Languages: interface_en
- Summary: Web and API service for checking AI-generated images and other synthetic media; free starter credits require an account.
- Use case: Useful for reproducible image checks and technical tests with API output.
- Caution: Results depend on file format, editing and generator. A negative result does not rule out AI generation.
- Last checked: 2026-09-04
- URL: https://sightengine.com/detect-ai-generated-images

## 21. Illuminarty
- Provider: Illuminarty
- Categories: ai_image_detector, api
- Access: free_limited_premium
- Inputs: image, api
- Languages: interface_en
- Summary: Image detector for potentially AI-generated, synthetic or manipulated images, with optional advanced functions and an API.
- Use case: A quick additional comparison for image material and possible local manipulation.
- Caution: Localisation and generator attribution are probabilistic. Do not upload confidential or personal images without reviewing the terms.
- Last checked: 2026-09-04
- URL: https://illuminarty.ai/en/

## 22. OpenAI Verify
- Provider: OpenAI
- Categories: ai_image_detector, authorship_evidence
- Access: free_no_account
- Inputs: image, audio
- Languages: interface_en
- Summary: Official verification tool for provenance signals such as C2PA metadata or watermarks in supported image and audio files from OpenAI tools.
- Use case: Especially useful when checking whether a file contains verifiable OpenAI provenance signals.
- Caution: This is not a general detector for every AI generator. Missing provenance signals do not prove that a file was human-created.
- Last checked: 2026-09-04
- URL: https://openai.com/research/verify/