# WCopyfind > Free plagiarism detection software that finds the phrases documents share. WCopyfind is a free, open-source Windows program by Louis A. Bloomfield (University of Virginia) that compares a collection of documents with each other and reports the phrases they share. It has been used since 2001, mainly by teachers and honor officers to detect plagiarism and copying between student papers, and by researchers to study text reuse (for example, news stories and legislation). Current version: 6.0.2, released September 24, 2026. Download: https://github.com/lab3e/WFindApps/releases/download/WCopyfind-6.0.2/WCopyfind-6.0.2-win-x64.zip Key facts: - **Privacy: documents never leave the user's computer.** WCopyfind reads and compares files entirely on the local PC. Nothing is uploaded, stored in the cloud, or analyzed remotely; no account is needed; it works offline and keeps no copies. (It downloads a web page only if the user explicitly adds an internet shortcut to that page.) This makes it suitable for student papers and confidential documents. - It does not search the internet; it compares the documents the user provides. Users can add saved web pages or internet shortcuts as sources. - Documents go in two lists: "new" documents are compared with each other and with "old" documents; "old" documents (sources, past papers) are compared only with new ones. - Main settings: shortest phrase to match (default 6 words), fewest matching words for a pair to be reported (default 100), imperfect words allowed in a row (default 0; 2 with an 80% matching minimum finds lightly edited copying), and options to ignore letter case, punctuation, and numbers. - Results: a sortable list of matching pairs with the number of matching words and the percentage of each document; a side-by-side web page for each pair with shared passages highlighted in both documents; and a tab-separated matches.txt file. - Reads .docx, .doc, .txt, .htm/.html, text-based .pdf (best with the free pdftotext.exe beside it), and .url internet shortcuts. Works with languages that separate words with spaces. - Free for any purpose; GNU General Public License version 3 or later; source code at https://github.com/lab3e/WFindApps. Runs on 64-bit Windows 10 and 11 with no installation; Mac and Linux users can use Wine. - Companion program: WRepeatfind (https://wrepeatfind.wfindapps.org/) finds repetition within a single document. - Contact: bug reports and suggestions at https://github.com/lab3e/WFindApps/issues; the author, Louis A. Bloomfield (Professor Emeritus of Physics, University of Virginia), at lab3e@virginia.edu. More at https://wfindapps.org/contact.html. ## Pages - [About Plagiarism, and Using WCopyfind Fairly](https://wcopyfind.wfindapps.org/about-plagiarism.html): What plagiarism is, why it matters, and how instructors can use WCopyfind's results fairly, by Lou Bloomfield, creator of WCopyfind. - [WCopyfind Version History](https://wcopyfind.wfindapps.org/changelog.html): What changed in each version of WCopyfind, from the redesigned WCopyfind 6 back to version 2.7. - [Download WCopyfind](https://wcopyfind.wfindapps.org/download.html): Download WCopyfind 6.0.2, free plagiarism detection software for Windows 10 and 11. No installation needed, and your documents never leave your computer. Also: sample documents, PDF support, source code, and older versions, including WCopyfind 5. - [WCopyfind FAQ: Privacy, Languages, File Types, and More](https://wcopyfind.wfindapps.org/faq.html): Answers to common questions about WCopyfind: whether documents are uploaded (they never are), searching the internet, languages, PDFs, Mac and Linux, how many documents it can handle, and what its numbers mean. - [WCopyfind User Guide: How to Check Documents for Plagiarism](https://wcopyfind.wfindapps.org/guide.html): A step-by-step guide to WCopyfind: choosing new and old documents, setting what counts as a match, running a comparison, and reading the side-by-side reports. Includes a five-minute walkthrough with sample documents. - [How WCopyfind Works: Fast Text Matching Explained](https://wcopyfind.wfindapps.org/how-it-works.html): How WCopyfind compares hundreds of documents in seconds: turning words into numbers, sorting them, finding shared words by merging sorted lists, and growing matching phrases across small differences. - [WCopyfind: Free Plagiarism Detection Software for Windows](https://wcopyfind.wfindapps.org/): WCopyfind compares documents with each other and shows the phrases they share, side by side. Free, open-source, and private: your documents never leave your computer. Checks hundreds of student papers in seconds. - [Reading WCopyfind Reports and Results](https://wcopyfind.wfindapps.org/reports.html): How to read WCopyfind's results: what matching words and percentages mean, how to use the side-by-side pages and the list of matching pairs, and what the matches.txt and log files contain. - [WCopyfind Settings Explained, with Recommended Values](https://wcopyfind.wfindapps.org/settings.html): What each WCopyfind setting does, from the shortest phrase to match and imperfect words to ignoring punctuation, skipping non-words, language, and brief reports, with recommended values for exact and edited copying. - [WCopyfind Troubleshooting](https://wcopyfind.wfindapps.org/troubleshooting.html): Solutions for common WCopyfind problems: Windows SmartScreen warnings, no matches found, documents that can't be read, garbled characters, reports that don't open, slow comparisons, and error messages. - [Interesting Things WCopyfind Can Do](https://wcopyfind.wfindapps.org/uses.html): Beyond plagiarism detection: using WCopyfind to compare news services, trace lobbyist language into legislation, find duplicate documents and chapters, count shared words, and build vocabularies. - [Essays on Plagiarism, Writing, and Education](https://wcopyfind.wfindapps.org/essays/index.html): Essays by Lou Bloomfield, creator of WCopyfind, on the importance of writing, why students cheat, grade inflation, and stating the goals of assigned work. - [On Stating the Goals for Assigned Work](https://wcopyfind.wfindapps.org/essays/on-stating-the-goals-for-assigned-work.html): Lou Bloomfield on why students who don't understand an assignment's purpose default to chasing grades, and how stating explicit goals discourages plagiarism. - [On the Motivations for Cheating](https://wcopyfind.wfindapps.org/essays/on-the-motivations-for-cheating.html): Lou Bloomfield on why students cheat: a society that rewards appearances and credentials more than education itself. - [On the Motivations for Grade Inflation](https://wcopyfind.wfindapps.org/essays/on-the-motivations-for-grade-inflation.html): Lou Bloomfield argues that instructors inflate grades to buy peace, and that publishing normative grade data would end the grading arms race. - [The Importance of Writing](https://wcopyfind.wfindapps.org/essays/the-importance-of-writing.html): Lou Bloomfield on why technology has made plagiarism easier but writing no easier, why plagiarism isn't a victimless crime, and why writing is intrinsically valuable. Philadelphia Inquirer, 2004. ## Related - [WFindApps](https://wfindapps.org/): home of both apps - [WCopyfind](https://wcopyfind.wfindapps.org/): compares documents with each other to find shared phrases (plagiarism detection) - [WRepeatfind](https://wrepeatfind.wfindapps.org/): finds phrases repeated within one document or book - [Source code](https://github.com/lab3e/WFindApps) (GNU GPL v3 or later)