All online tools to detect duplicate content and plagiarism

Last updated on 12 May 2026

How to detect plagiarism? The web is full of tools that make it possible in a few seconds to check whether a text is original or whether it is a more or less skilful plagiarism. Online tools for detect plagiarism and copy and paste it They have become indispensable in our digital world.

A veritable Google-era epidemic. How to detect plagiarism in a memory? Sometimes there are doubts when reading a text. Sometimes they are also unfounded.  Plagiarism is a phenomenon long known and listed in the academic world. It touches today all grade levels from primary to high school.

Another practice that spreads at lightning speed is theuse of new AI-enabled writing tools. Many young people were amazed at the power of a tool like ChatGPT that can produce text on all topics from a simple statement. Before the training necessary for a reasoned and ethical use of these new tools makes it possible to limit the breakage, there is a great risk that some students will forget to think about turning to the ‘magic’ of iA.

However, the first tools to detect not plagiarism but the use of iA-assisted writing are also beginning to appear.

So how do you know if a text comes from the Internet? While this practice continues to grow, there are tools to help teachers detect plagiarists. Here are 11 of them.

How to detect Copy-paste? Here are eleven online tools to detect plagiarism.

Plagtracker

PlagTracker is a powerful tool with a particularly efficient algorithm that will scan your document and compare it to its base of 20 million referenced documents and everything you can find online. An interesting feature: PlagTracker allows you to upload a text document. The tool will scan it and then send you a full report by email with all the sources of the copied items. Plagtracker offers a limited free version and another paid version. 

Plagiarism

Plagiarism is another online tool for detecting plagiarism. It is capable of handling more than 190 languages. Very easy to use, it allows verification of plagiarism by copying and pasting text or by importing a file to analyze. The tool supports TXT, HTML, RTF, DOC, DOCX, XLS, XLSX, PDF, ODT, EPUB, FB2, PDB formats. A real Swiss knife. A free version allows a limited number of checks.

Plagiarism Checker

PlagiarismChecker is a free anti plagiarism software. It plays with simplicity and will allow you to do a quick check in case of doubt about a passage in a copy. PlagiarismChecker offers a window in which you will copy the passage of the text on which you have a doubt. The results are displayed almost instantly if the passage exists somewhere on the web. Plagiarism Checker is completely free. 

Viper

Viper is a particularly powerful weapon for detecting duplicate content. It offers verification with millions of sources, an easy-to-use interface, and a comprehensive report on each analysis. Each questionable passage is highlighted in order to be easily located. Viper also shows the full URL of all matching sources so you can find the original content and easily compare the result on your own. Viper invoices on a fee-for-service basis. Count a little more than one euro per check.

PlagSpotter

PlagSpotter occupies a somewhat separate place in this list. This anti-plagiarism tool seeks to check and then monitor whether the content of a website or blog has been copied or plagiarised. The result shows all dubious covers with links that allow you to visit them. A Premium subscription offers as a bonus the possibility to install a watch to be alerted in the event of a new publication.

Search Engine Report

Search Engine Report offers a free content duplication checker for teachers. You can copy paste the text you want to control or download a file from your computer or Dropbox account. The tool works in around 20 different languages and allows texts of up to 1500 words to be checked free of charge.

Duplichecker

Duplichecker works a little in the same way as everyone else. POur detect plagiarism; you must paste your text in the box provided for this purpose. It goes a step further by allowing you to upload an archive or indicate a URL to ask it to look for copies or plagiarism. Again the service is free .You can use it without registering. A paid Pro version offers additional search functions.

Copyscape

Copyscape is an even more complete tool but here you will have to pay a few cents for each search. Simply paste the link you want to check or an excerpt from the text and then start the search. If you are a website editor, Copyscape offers you a logo in the form of a label that aims to do a little pedagogy with potential copiers. To use Copyscape you will need to register for the service and purchase credits to use it.

Quetext

Quetext is particularly suitable for detecting plagiarism in the academic field. It uses a particularly efficient DeepSearch technology. The software searches for many sources of duplicate content and among them: Online Books, web pages, news articles, academic publications, etc. The results allow a good exploitation with text, excerpts, comments and a percentage of plagiarism. The tool is free for texts up to 2500 words.

PrepostSeo

PrepostSeo is part of a large toolkit for online content publishers. Among other utilities, the site offers a fairly efficient tool for detecting pagiats and duplicated content. Just copy your text and paste it into the given input box, then select the language to start the verification. The result offers a plagiarized and unique content percentage.

GPTZero

GPTZero presented on the Artificial Intelligence Tools website holds a special place in this list. GPTZero is the first rather serious tool to tackle the devastation caused by the famous ChatGPT. A writing tool with iA capable of automatically producing texts on almost any topic.

GPTZero is a valuable weapon. Developed by a young South African student, this tool makes it possible to detect texts produced with ChatGPT. It is unreliable at 100%. But in case of doubt, it can give valuable indications.

So much for these eleven tools. If you know of others, please feel free to give me the references in comment.