# Plagiarism Checker Plus > Plagiarism Checker Plus is a free writing-integrity platform that checks text for plagiarism and AI-generated content. It scans against billions of web pages, journals, and academic sources, returns a sentence-level similarity report with linked sources, and flags passages likely written by ChatGPT, Claude, Gemini, or Llama. No account is required for a first check, and submitted text is never shared, or used to train AI. ## Tools - [Plagiarism Checker](https://plagiarismcheckerplus.com/): Scan text against billions of web pages, journals, and academic sources. Returns an originality score, sentence-level highlights, and a linked source list. - [AI Detector](https://plagiarismcheckerplus.com/ai-detector): Detect whether text was written by ChatGPT, Claude, Gemini, Llama, or other large language models. Returns an overall AI score, per-sentence highlights, and a confidence rating for each flag. - [AI Detector for Essays](https://plagiarismcheckerplus.com/ai-detector-for-essays): Check an essay for AI writing with an overall score and a likelihood for each sentence. - [ChatGPT Checker](https://plagiarismcheckerplus.com/chatgpt-checker): Check whether text reads as written by ChatGPT or another large language model, with a score for each sentence. - [AI Detector for Teachers](https://plagiarismcheckerplus.com/ai-detector-for-teachers): Sentence-level AI check for student work, with guidance on fair process. - [Paper Checker](https://plagiarismcheckerplus.com/paper-checker): Grammar, plagiarism and AI check for research papers and term papers. - [Grammar Checker](https://plagiarismcheckerplus.com/grammar-checker): Fix grammar, spelling, and clarity issues. - [Citation Generator](https://plagiarismcheckerplus.com/citation-generator): Generate references in APA, MLA, Chicago, and Harvard. ## Key facts - Free first check, no account or card required. - Combined plagiarism + AI detection in a single scan and one unified report. - Sentence-level analysis with confidence ratings, not just one overall percentage. - Privacy: text is processed in real time and not retained after the scan; free scans are not stored. - AI detection is a probabilistic signal and should never be the sole basis for an academic-integrity decision. - Multi-language support (English, Spanish, French, German, Portuguese, Italian, Hindi, Arabic, Dutch, Chinese, and more). - For teachers, students, professionals, publishers, and institutions; bulk upload and API access available. ## More - [Pricing](https://plagiarismcheckerplus.com/pricing) - [How detection works](https://plagiarismcheckerplus.com/technology) - [Plagiarism Checker for Students](https://plagiarismcheckerplus.com/plagiarism-checker-for-students): Guide to checking essays, theses, and assignments for plagiarism before submission. - [Plagiarism Checker for Content Writers](https://plagiarismcheckerplus.com/plagiarism-checker-for-content-writers): Check an article for copied text and AI-written passages before publishing. - [Plagiarism Checker for Teachers](https://plagiarismcheckerplus.com/plagiarism-checker-for-teachers): Guide to checking student work and upholding academic integrity. - [Contact / API access](https://plagiarismcheckerplus.com/contact) - [Brand guidelines and logos](https://plagiarismcheckerplus.com/brand): Logo downloads, brand colours, typeface, ready-made descriptions and how to write our name. ## Integrations - [Google Docs add-on](https://plagiarismcheckerplus.com/integrations/google-docs-add-on): Check a document for plagiarism, AI writing and grammar without leaving Google Docs. - [Chrome extension](https://plagiarismcheckerplus.com/integrations/chrome-extension): Highlight text on any page and check it for AI writing or plagiarism. - [MCP connector](https://plagiarismcheckerplus.com/integrations/mcp): Check text for plagiarism and AI writing from an AI assistant over a remote MCP server. - [API](https://plagiarismcheckerplus.com/integrations/api): Plagiarism and AI detection over a REST API. ## Guides - [What is plagiarism?](https://plagiarismcheckerplus.com/guides/what-is-plagiarism): The types universities look for, with a paraphrasing example. - [Types of plagiarism](https://plagiarismcheckerplus.com/guides/types-of-plagiarism): Direct, mosaic, patchwork, incremental, global, source-based and AI-assisted, each with an example. - [Plagiarism examples](https://plagiarismcheckerplus.com/guides/plagiarism-examples): Twelve invented examples by type, each with the original, the student version, why it counts and the fixed version. - [Is paraphrasing plagiarism?](https://plagiarismcheckerplus.com/guides/is-paraphrasing-plagiarism): The yes/no answer, where the line is, and a side-by-side example of an acceptable and a plagiarized paraphrase. - [Direct plagiarism](https://plagiarismcheckerplus.com/guides/direct-plagiarism): Word-for-word copying with no quotation marks and no credit. A marked example and the two honest ways to fix it. - [Patchwriting](https://plagiarismcheckerplus.com/guides/patchwriting): A paraphrase that only swaps words and keeps the source's sentence. A marked example, and how to rewrite it properly. - [Global plagiarism](https://plagiarismcheckerplus.com/guides/global-plagiarism): Submitting a whole work someone else wrote. Examples, and how it differs from patchwork and incremental plagiarism. - [Incremental plagiarism](https://plagiarismcheckerplus.com/guides/incremental-plagiarism): An uncredited quote, fact or paraphrase inside mostly original work. Before and after examples for speeches and essays. - [How much plagiarism is allowed?](https://plagiarismcheckerplus.com/guides/how-much-plagiarism-is-allowed): Why no amount is allowed, what a similarity percentage really means, and why there is no universal threshold. - [How do plagiarism checkers work?](https://plagiarismcheckerplus.com/guides/how-do-plagiarism-checkers-work): How a checker compares your text with other sources, what the score means, and what it can miss. - [How to check plagiarism in Google Docs](https://plagiarismcheckerplus.com/guides/how-to-check-plagiarism-in-google-docs): Three ways to check a Google Doc for plagiarism, with the steps for each. - [How to tell if something is written by AI](https://plagiarismcheckerplus.com/guides/how-to-tell-if-something-is-written-by-ai): 12 signs of AI writing you can spot by eye, each with an example, and why no single sign is proof. - [How to check for AI writing](https://plagiarismcheckerplus.com/guides/how-to-check-for-ai-writing): A 6-step process for checking a text for AI: detector, signs, sources, earlier work, drafts and a conversation. - [AI detector false positives](https://plagiarismcheckerplus.com/guides/ai-detector-false-positives): Why AI detectors flag human writing, what the research says, and what students and teachers should do about a flag. - [Do AI detectors work?](https://plagiarismcheckerplus.com/guides/do-ai-detectors-work): What AI detectors get right, where they fail, what the research shows, and how to use a score responsibly. - [Do colleges use AI detectors?](https://plagiarismcheckerplus.com/guides/do-colleges-use-ai-detectors): How colleges check coursework and admissions essays for AI, and why the answer differs by school. - [Does Common App check for AI?](https://plagiarismcheckerplus.com/guides/does-common-app-check-for-ai): What Common App's own policy says about AI-generated content in an application. - [Does Blackboard detect AI?](https://plagiarismcheckerplus.com/guides/does-blackboard-detect-ai): What SafeAssign checks, when Turnitin adds an AI report, and what Blackboard's logs show instructors. - [How to cite a quote](https://plagiarismcheckerplus.com/guides/how-to-cite-a-quote): In-text formats for direct quotes in APA, MLA and Chicago: short quotes, block quotes, missing page numbers and a quote within a quote. - [How to cite a podcast](https://plagiarismcheckerplus.com/guides/how-to-cite-a-podcast): Copy-ready APA, MLA and Chicago formats for a podcast episode, with timestamps and episodes heard in an app. - [How to cite a tweet](https://plagiarismcheckerplus.com/guides/how-to-cite-a-tweet): How to cite a tweet or X post in APA, MLA and Chicago, including images, emojis, threads and the Twitter-or-X question. - [APA format in Google Docs](https://plagiarismcheckerplus.com/guides/apa-format-google-docs): Set up an APA 7 paper in Google Docs: font, spacing, margins, title page, page numbers, headings and the hanging indent. - [How to write an annotated bibliography](https://plagiarismcheckerplus.com/guides/how-to-write-an-annotated-bibliography): The six steps, what goes in an annotation, how long it should be, and APA, MLA and Chicago formats with an example of each. - [Best free AI detectors](https://plagiarismcheckerplus.com/guides/best-free-ai-detectors): What eight free AI detectors really give you: word limits, daily checks, sign-up and sentence results, from each maker's own site. - [Best AI detectors for teachers](https://plagiarismcheckerplus.com/guides/best-ai-detectors-for-teachers): Six AI detectors compared by what a teacher needs: sentence evidence, cost for one teacher, LMS integration, privacy and vendor warnings. - [Turnitin alternatives](https://plagiarismcheckerplus.com/guides/turnitin-alternatives): Turnitin is not sold to individuals. Eight checkers you can use alone, compared on free limits, sign-up, AI detection and price. - [Is Turnitin free?](https://plagiarismcheckerplus.com/guides/is-turnitin-free): Turnitin is free to students whose school pays for it, and it is not sold to individuals. Prices, access and options. - [Turnitin checker: what you can use](https://plagiarismcheckerplus.com/guides/turnitin-checker): Turnitin sells no checker to students. Three real ways to check a paper first, and why no tool can predict your score. - [Scribbr alternatives](https://plagiarismcheckerplus.com/guides/scribbr-alternatives): Six tools compared on free limits, price per document or per month, plagiarism checks and AI detection. - [GPTZero alternatives](https://plagiarismcheckerplus.com/guides/gptzero-alternatives): Six tools compared on free word limits, paid price, plagiarism checks and AI detection. - [Grammarly alternatives for plagiarism and AI checks](https://plagiarismcheckerplus.com/guides/grammarly-alternatives): Six tools compared on the two checks only: plagiarism and AI detection, with free limits and price. - [Copyleaks vs Turnitin](https://plagiarismcheckerplus.com/guides/copyleaks-vs-turnitin): Who can buy each one, how you reach it, AI detection, stated limits and price, taken from each vendor's own pages. - [Is ZeroGPT accurate?](https://plagiarismcheckerplus.com/guides/is-zerogpt-accurate): What ZeroGPT claims, what published tests found, and why the results differ so much. - [Is QuillBot’s AI detector accurate?](https://plagiarismcheckerplus.com/guides/is-quillbot-ai-detector-accurate): QuillBot’s 99% claim beside the small studies that name it. - [Is Grammarly’s AI detector accurate?](https://plagiarismcheckerplus.com/guides/is-grammarly-ai-detector-accurate): What Grammarly says about its score, and why no independent test exists yet. - [Is Copyleaks accurate?](https://plagiarismcheckerplus.com/guides/is-copyleaks-accurate): Copyleaks’ own figures beside a 2026 peer-reviewed test of 160 papers. - [Is Originality.ai accurate?](https://plagiarismcheckerplus.com/guides/is-originality-ai-accurate): Its claims by model, and what a 2026 peer-reviewed test found. - [GPTZero vs ZeroGPT](https://plagiarismcheckerplus.com/guides/gptzero-vs-zerogpt): Two separate detectors with similar names, compared with facts from each maker. - [QuillBot alternatives for plagiarism and AI checks](https://plagiarismcheckerplus.com/guides/quillbot-alternatives): Six tools compared on the checks only: free limits, price, plagiarism and AI detection. - [Turnitin Draft Coach](https://plagiarismcheckerplus.com/guides/turnitin-draft-coach): What it checks, who can get it, its limits, and what to do if your school does not have it. - [Plagiarism checker with percentage](https://plagiarismcheckerplus.com/guides/plagiarism-checker-with-percentage): Get a match percentage free, then learn what the number means and why tools differ. - [ZeroGPT vs Turnitin](https://plagiarismcheckerplus.com/guides/zerogpt-vs-turnitin): Why a ZeroGPT score does not predict a Turnitin score, with what each vendor says about access, limits and errors. - [Plagiarism Checker Plus vs Turnitin](https://plagiarismcheckerplus.com/guides/plagiarism-checker-plus-vs-turnitin): Turnitin is a school system the instructor controls. Plagiarism Checker Plus is self-serve. What each does, and why one cannot predict the other. - [Plagiarism Checker Plus vs Copyleaks](https://plagiarismcheckerplus.com/guides/plagiarism-checker-plus-vs-copyleaks): Our checker against Copyleaks, attribute by attribute, including where Copyleaks is the better choice. - [Plagiarism Checker Plus vs ZeroGPT](https://plagiarismcheckerplus.com/guides/plagiarism-checker-plus-vs-zerogpt): Our checker against ZeroGPT, attribute by attribute, including where ZeroGPT is the better choice. - [Mosaic plagiarism](https://plagiarismcheckerplus.com/guides/mosaic-plagiarism): Definition, a marked example, and how it differs from direct plagiarism and patchwriting. - [Self-plagiarism](https://plagiarismcheckerplus.com/guides/self-plagiarism): When reusing your own work breaks the rules and how to do it properly. - [Is plagiarism illegal?](https://plagiarismcheckerplus.com/guides/is-plagiarism-illegal): When plagiarism is a policy violation and when it becomes copyright infringement or fraud. - [Is using AI plagiarism?](https://plagiarismcheckerplus.com/guides/is-using-ai-plagiarism): How schools and publishers treat AI-written text. - [How to avoid plagiarism](https://plagiarismcheckerplus.com/guides/how-to-avoid-plagiarism): Quoting, paraphrasing and citing correctly. - [How to paraphrase without plagiarizing](https://plagiarismcheckerplus.com/guides/how-to-paraphrase-without-plagiarizing): A step-by-step method with examples. - [How to interpret a plagiarism report](https://plagiarismcheckerplus.com/guides/how-to-interpret-a-plagiarism-report): What a similarity score does and does not show. - [How AI detectors work](https://plagiarismcheckerplus.com/guides/how-ai-detectors-work): What AI detectors measure, their limits and false positives. - [How do teachers check for AI?](https://plagiarismcheckerplus.com/guides/how-do-teachers-check-for-ai): The methods teachers use and what counts as evidence. - [Does Canvas have AI detection?](https://plagiarismcheckerplus.com/guides/does-canvas-have-ai-detection): What Canvas can and cannot detect on its own. - [Does SafeAssign detect AI?](https://plagiarismcheckerplus.com/guides/does-safeassign-detect-ai): SafeAssign is a text-matching plagiarism tool with no AI score; what Blackboard's documentation says. - [Can Google Classroom detect AI?](https://plagiarismcheckerplus.com/guides/can-google-classroom-detect-ai): Originality reports match text against web pages and books; Google's help pages describe no AI score. - [Does ChatGPT plagiarize?](https://plagiarismcheckerplus.com/guides/does-chatgpt-plagiarize): Whether ChatGPT output copies existing text, and when submitting it counts as plagiarism. - [What percentage of AI is acceptable?](https://plagiarismcheckerplus.com/guides/what-percentage-of-ai-is-acceptable): There is no universal acceptable AI percentage; the policy matters, not the number. - [How to prove you didn't use AI](https://plagiarismcheckerplus.com/guides/how-to-prove-you-didnt-use-ai): Checklist for a student whose own work was flagged: report, drafts, version history, appeal. - [Accidental plagiarism](https://plagiarismcheckerplus.com/guides/accidental-plagiarism): How unintentional plagiarism happens, whether intent matters, and how to fix it. - [Consequences of plagiarism](https://plagiarismcheckerplus.com/guides/consequences-of-plagiarism): Typical outcomes for students, researchers and professionals. - [Can Google detect AI content?](https://plagiarismcheckerplus.com/guides/can-google-detect-ai-content): Google's documentation says it evaluates quality and intent, not whether text is AI-written. - [Is AI content bad for SEO?](https://plagiarismcheckerplus.com/guides/is-ai-content-bad-for-seo): What Google's guidance says about AI content, scaled content abuse and disclosure. - [Duplicate content and SEO](https://plagiarismcheckerplus.com/guides/duplicate-content-seo): Canonical URLs, when copied content becomes a spam-policy problem, and how to fix duplicates. - [Best plagiarism checkers for students](https://plagiarismcheckerplus.com/guides/best-plagiarism-checkers-for-students): Six plagiarism checkers compared by student need, not ranked, with facts from each maker's own site. Written by the maker of one of them. - [How to check for plagiarism](https://plagiarismcheckerplus.com/guides/how-to-check-for-plagiarism): Step-by-step method: run a check, read each match, then quote, cite or rewrite. - [How to detect plagiarism in student essays](https://plagiarismcheckerplus.com/guides/how-to-detect-plagiarism-in-student-essays): Signs worth a closer look and a fair process for teachers. - [Can professors detect ChatGPT?](https://plagiarismcheckerplus.com/guides/can-professors-detect-chatgpt): How ChatGPT use gets noticed and what a detector can and cannot prove. - [Does Turnitin detect AI?](https://plagiarismcheckerplus.com/guides/does-turnitin-detect-ai): What Turnitin's own documentation says about its AI writing detection, word minimums and false positives. - [How to cite a website](https://plagiarismcheckerplus.com/guides/how-to-cite-a-website): APA 7, MLA 9 and Chicago formats, with fixes for no author and no date. - [How to cite a YouTube video](https://plagiarismcheckerplus.com/guides/how-to-cite-a-youtube-video): APA 7, MLA 9 and Chicago examples with timestamps. - [How to cite ChatGPT](https://plagiarismcheckerplus.com/guides/how-to-cite-chatgpt): APA, MLA and Chicago formats for AI tools, and what to disclose. - [How to cite an image](https://plagiarismcheckerplus.com/guides/how-to-cite-an-image): Templates for photos, artworks, Google Images, stock photos and AI images. - [How to cite a PDF](https://plagiarismcheckerplus.com/guides/how-to-cite-a-pdf): Cite the document inside the PDF, with fixes for no author, date or page numbers. - [MLA format in Google Docs](https://plagiarismcheckerplus.com/guides/mla-format-google-docs): Font, spacing, margins, header, Works Cited and the hanging indent. ## Common questions - [Can Google Docs detect AI?](https://plagiarismcheckerplus.com/help/can-google-docs-detect-ai): Google Docs has no built-in AI detector; what version history shows and how to check a document. - [How to check Google Docs for AI](https://plagiarismcheckerplus.com/help/how-to-check-google-docs-for-ai): Steps to check a Google Doc for AI writing with the add-on. - [Does Google Docs have a plagiarism checker?](https://plagiarismcheckerplus.com/help/does-google-docs-have-a-plagiarism-checker): What Google Docs includes and how to check a document for plagiarism. - [How to check for plagiarism in Google Docs](https://plagiarismcheckerplus.com/help/how-to-check-for-plagiarism-in-google-docs): Step-by-step check inside a document. - [Understanding your similarity score](https://plagiarismcheckerplus.com/help/understanding-your-similarity-score): What the percentage means and why there is no universal safe number. - [What happens to my text](https://plagiarismcheckerplus.com/help/what-happens-to-my-text): How submitted text is handled. - [Help Center](https://plagiarismcheckerplus.com/help): All how-to articles. ## News - [Academic integrity and AI in education news](https://plagiarismcheckerplus.com/news): Dated reports on university AI policies, detector research and court cases, each linking to original sources. - [Editorial standards](https://plagiarismcheckerplus.com/news/editorial-standards): How news is sourced, corrected and updated. ## Other languages - [Español: detector de plagio, detector de IA y guías](https://plagiarismcheckerplus.com/es): Spanish tools and guides, including [¿Turnitin detecta IA?](https://plagiarismcheckerplus.com/es/guias/turnitin-detecta-ia) and [¿Se puede usar Turnitin gratis?](https://plagiarismcheckerplus.com/es/guias/turnitin-gratis). - [Português: detector de plágio, detector de IA e guias](https://plagiarismcheckerplus.com/pt): Portuguese (Brazil) tools and guides. - [Deutsch: Plagiatsprüfung, KI-Detektor und Rechtschreibprüfung](https://plagiarismcheckerplus.com/de): German tools. - [Polski: antyplagiat, detektor AI i sprawdzanie pisowni](https://plagiarismcheckerplus.com/pl): Polish tools. - [Nederlands: plagiaat checker, AI-detector en spellingscontrole](https://plagiarismcheckerplus.com/nl): Dutch tools. ## Optional - [Privacy Policy](https://plagiarismcheckerplus.com/privacy) - [Terms of Service](https://plagiarismcheckerplus.com/terms) - [Refund Policy](https://plagiarismcheckerplus.com/refund-policy) - [DMCA Notice & Takedown Policy](https://plagiarismcheckerplus.com/dmca)