About WFindApps

WFindApps is the home of two free programs that find matching language in documents: WCopyfind and WRepeatfind.

How it started

In 2001, Lou Bloomfield, a professor of physics at the University of Virginia, wrote a program to compare the term papers in his large introductory physics course, because checking hundreds of papers against one another by eye is impossible. It uncovered extensive plagiarism, and he spent the next two years dealing with the honor cases that followed. He has written about what he learned from that experience in his essays on plagiarism and writing.

He decided to share the program freely, so that any teacher could check their own students' work without paying for a service or sending the papers to a company. That program became WCopyfind, and it has been downloaded and used by teachers, honor officers, researchers, and writers around the world ever since.

What's new

In 2026, WCopyfind was thoroughly modernized: a redesigned window, side-by-side reports that work in today's browsers, better reading of Word and PDF files, and many long-standing bugs fixed. And a new companion program, WRepeatfind, turned WCopyfind's engine inward, to find the phrases a single document repeats. Readers of the old Plagiarism Resource Site had been asking for exactly that for years.

WFindApps.org brings the two programs together, with complete guides for each. See the news page for the history of releases.

Open source

Both programs are free software, released under the GNU General Public License, version 3 or later. You're free to use them for any purpose, share them, study how they work, and improve them. If you distribute a changed version, you must share its source code under the same license. The source code is on GitHub.

Privacy

The programs have always worked the same way: on your own computer, with your own files. They never upload your documents. That's by design, and it will stay that way. See the privacy statement.

About the author

Louis A. Bloomfield is Professor Emeritus of Physics at the University of Virginia. For many years he taught How Things Work, a popular course on the physics of everyday life, and he wrote the book of the same name. He has long been interested in writing, authorship, and academic integrity, and in the ways language moves through society. As an academic, he welcomes collaborations that use these tools to study large collections of documents. You can reach him at lab3e@virginia.edu; see Contact for his postal address and for reporting problems.

The Plagiarism Resource Site

For many years WCopyfind lived at the Plagiarism Resource Site. Its essays and instructions have moved here, updated for the current versions, and older versions of WCopyfind remain available from the WCopyfind download page.