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The best free websites to detect plagiarism in texts

22 mayo, 2021

The Royal Academy of the Language defines plagiarism as the action of “to substantially copy other people’s works, giving them as their own”. On a day-to-day basis, it is the professionals of formal education who most frequently have to deal with this kind of ploy.

Even if there are powerful payment tools that allow detecting plagiarism by comparing them with databases with thousands of documents not freely available on the Internet, it is not the type of software that the average educator can usually afford, due to its cost.

And even less, any user who only needs this functionality in a specific way. For them, we have compiled some of the main free online tools dedicated to plagiarism detection.

Alert, politicians: this is how plagiarism detection tools work in universities


Let’s start with a simple tool: Quetext. Cleaner interface than most of its rivals, offers little or no choice to the user (we can only copy and paste the text to be analyzed) and click on ‘Check plagiarism’.

Yes indeed: from what we have been able to verify, it is fast and accurate, and offers us a list of URLs with matches accompanied by the percentage of plagiarized text.

The only ‘extra’ it offers us is un wizard to cite the original source with the proper format, in case we were verifying any unattributed citation of an academic work.

Dupli Checker

Dupli Checker is a free tool that does not even require user registration. As soon as we explore, we will discover that this website houses a multitude of web positioning and text analysis tools, but Its main functionality and the first that we will find when we open the web, is that of plagiarism detection.

Dupli Checker will turn to Google and Bing to search for texts that match the one entered and present you with the links and the corresponding match percentages.

Partially translated into Spanish, once the possible sources of the text have been found, it will offer us several options, including ‘Compare text’ (opening the original web within a frame, with the affected text highlighted in color) and ‘Make it Unique ‘ (a function dedicated rather to plagiarists who seek to cure themselves in health and try to make the percentage of text detected as plagiarism as low as possible).

€ 14 per page, plagiarism-proof, safe approved: the business of the TFG and the TFM on request


Plagiarism is another of the free tools commonly used for spot checks. In principle it provides a limit of 2,000 characters per scan and it only looks for matches using Bing technology, but if we register on the web (for free) the character limitation disappears and the possibilities of its search engine are expanded thanks to the use of Google technology (Also search Google Scholar and Google Books).

Like the previous one, it offers the options of copying and pasting text, entering a URL or uploading the file containing the text to be analyzed (in 12 different formats). What’s more, It has applications for Android mobiles and for Windows computers, in addition to a version as a complement to the Moodle e-learning manager, which makes life easier for teachers.



The Copyleaks website promises the user “detect plagiarism, paraphrased content and similarities between texts using algorithms of artificial intelligence in more than 100 languages ​​”.

Although it is not free, yes offers a somewhat limited plan for free that restricts the number of words and analyzable pages, in addition to not allowing access to several of its extra functions (integration with Moodle and office software, downloading of reports, etc.).

Its ‘text scan’ tool is more comprehensive than most of its free rivals– Allows you to search both the Internet and Copyleaks’ own databases (or both), and exclude items such as explicit citations, headlines, and tables of contents from text checking. and the plagiarism of its contents without permission are the best example of one of the great problems of the Internet


PlagScan is a paid tool that, however, offers a free trial That may be more than enough for a quick check. Like other websites, it offers a compilation of matching results on Internet pages, having been one of the most exhaustive of the proven tools.

In exchange for a free registration, tIt also gives us the option to generate a report on each search. However, at least in the trial version, we have detected a notable discrepancy between the results of the web and those of the generated report.

Image | Maik meid