Grammarly free plagiarism checker versus Turnitin and Quillbot plagiarism checkers -tested

16 May 202306:57

TLDRIn this video comparison, Grammarly's free plagiarism checker is tested against Turnitin and Quillbot. The results show that Grammarly failed to detect plagiarism in multiple instances where Turnitin and Quillbot successfully identified copied content. Turnitin's results were particularly notable, with a 99% similarity score for a verbatim copied text. The video highlights the limitations of relying solely on Grammarly for plagiarism detection.


  • 🔍 Grammarly offers a free plagiarism checker that claims to compare documents to 16 billion web pages.
  • 📈 In testing, Grammarly reported no plagiarism for a 2,000-word document, while Quillbot found a 46% match, indicating significant similarities.
  • 🔎 Turnitin detected a 64% similarity score for the same document, suggesting direct copying and paraphrasing.
  • 🏫 Turnitin also scans student repositories, including university submissions, which can affect similarity scores.
  • 🔄 In a second test, Grammarly failed to consistently identify plagiarism in a text that was clearly copied from the internet.
  • 💯 When a paragraph copied verbatim from a single source was tested, Turnitin showed a 99% similarity score, indicating academic misconduct.
  • 📄 For a lengthy academic paper (8 pages) that was publicly available, Grammarly reported no plagiarism, whereas Turnitin and Quillbot found extremely high similarity scores.
  • 🌐 Quillbot's sources are often free and openly accessible, whereas Turnitin can identify sources from paid publications or those requiring institutional access.
  • ⚠️ The results suggest that Grammarly's plagiarism checker may not always detect copied content, especially in comparison to Turnitin and Quillbot.
  • 📊 It's important to be aware of the limitations and differences between plagiarism checkers when relying on them to ensure academic integrity.

Q & A

  • What is the main focus of the video?

    -The main focus of the video is to test and compare the effectiveness of Grammarly's free plagiarism checker against Turnitin and Quillbot plagiarism checkers.

  • How does Grammarly's plagiarism checker claim to function?

    -Grammarly's plagiarism checker claims to function by comparing documents to 16 billion web pages to identify any instances of plagiarism.

  • What was the result when the 2,000-word document was scanned by Grammarly?

    -When the 2,000-word document was scanned by Grammarly, it reported no instances of plagiarism found.

  • What was the outcome when the same document was checked by Quillbot?

    -When the same document was checked by Quillbot, it showed a 46% match, indicating that a significant portion of the content was identical or had minor changes.

  • How did Turnitin's results differ from Grammarly's?

    -Turnitin's results showed a 64% similarity score, indicating a higher amount of direct copying or paraphrasing compared to Grammarly's report of no plagiarism found.

  • What does Turnitin do differently from the other plagiarism checkers?

    -Turnitin scans the student repository, which includes submissions from universities where Turnitin is used, in addition to public domain sources.

  • What was the result when a paragraph copied verbatim from a single source was tested in Grammarly?

    -When a paragraph copied verbatim from a single source was tested in Grammarly, it initially reported no plagiarism found, but later inconsistently reported findings of plagiarism when the test was repeated.

  • What was the similarity score when the 8-page conference paper was tested in Turnitin?

    -When the 8-page conference paper was tested in Turnitin, it showed a 100% similarity score, indicating verbatim copying from the source.

  • How did Quillbot perform with the 8-page conference paper?

    -Quillbot found a 91.2% identical match for the 8-page conference paper, as it was copied directly from a public domain source.

  • What is an important consideration when comparing the sources located by Quillbot and Turnitin?

    -An important consideration is that Quillbot located free sources, whereas Turnitin located the publication site that hosts the article, which often requires payment or institutional login to access.

  • What conclusion does the video presenter draw about Grammarly's plagiarism checker?

    -The video presenter concludes that relying solely on Grammarly's plagiarism checker may not be sufficient, as it does not necessarily pick up all instances of plagiarism, as demonstrated by the results from Quillbot and Turnitin.



🔍 Comparing Plagiarism Checkers: Grammarly vs Turnitin vs Cobot

The video script begins with the host discussing a comparison between different plagiarism checking tools. The host uses Grammarly's free plagiarism checker, Turnitin, and Cobot to scan a document for plagiarism. Grammarly reports no plagiarism, while Cobot finds a 46% match, indicating both identical verbatim copying and minor changes. Turnitin's results show a 64% similarity score, suggesting significant direct copying and paraphrasing. The host also notes that Turnitin scans student repositories, which could affect results. The video demonstrates the inconsistency in Grammarly's results when scanning identical text, highlighting the potential limitations of relying solely on Grammarly for plagiarism checks.


📚 Public Domain Text and Plagiarism Checker Results

In this paragraph, the host uploads a text that is publicly available and compares the results from Grammarly, Turnitin, and Cobot. Grammarly incorrectly identifies the text as non-plagiarized, while Turnitin and Cobot correctly detect the high percentage of copied content. The host emphasizes the differences in the sources found by Cobot and Turnitin, noting that Cobot locates free sources, whereas Turnitin finds the publication site, which may require payment or institutional access. The host concludes by advising viewers to be cautious when relying on any single plagiarism checker, as each tool has its limitations and may not catch all instances of plagiarism.



💡Plagiarism checker

A plagiarism checker is a software tool that helps identify instances of plagiarism in text by comparing it against a large database of content from various sources. In the video, the user tests different plagiarism checkers, including Grammarly, Turnitin, and Quillbot, to see which one is most effective at detecting copied content. The main theme of the video is to compare the efficiency and accuracy of these tools in identifying plagiarism.


Grammarly is an online writing assistant that includes a plagiarism checker among its features. It helps users with grammar, spelling, and style improvements, as well as detecting potential plagiarism by comparing the user's text to a vast database of web pages. In the video, the user tests Grammarly's plagiarism checker functionality against other tools to evaluate its effectiveness.


Turnitin is a widely used plagiarism detection service that checks the originality of student papers and other documents by comparing them against a large database of academic papers, journals, and web content. It is particularly popular in academic institutions. In the video, Turnitin is one of the tools used for comparison to test its ability to detect plagiarism.


Quillbot is an online paraphrasing tool that can also function as a plagiarism checker. It helps users rephrase content to avoid plagiarism and provides a percentage match to identify copied content. In the video, Quillbot is used to compare its plagiarism detection capabilities with those of Grammarly and Turnitin.

💡Web pages

Web pages refer to the individual pages on the World Wide Web that can be accessed through the internet. In the context of the video, web pages are part of the database that plagiarism checkers, like Grammarly, use to compare and detect copied content from online sources.

💡Identical verbatim copying

Identical verbatim copying is when a piece of text is directly lifted from a source without any changes in words, order, or structure. This type of copying is considered plagiarism and is what plagiarism checkers aim to detect. In the video, the tools are evaluated on their ability to identify such instances of direct copying.

💡Minor changes

Minor changes refer to slight alterations made to the original text, such as changing a few words or using synonyms, with the intention of avoiding plagiarism detection. These changes, while not verbatim, still indicate the use of someone else's work without proper attribution.

💡Student repository

A student repository is a database that stores academic work submitted by students, often used by institutions to prevent plagiarism. Turnitin, for instance, has a student repository feature that checks for similarities with previously submitted works, helping educational institutions maintain academic integrity.

💡Academic misconduct

Academic misconduct refers to the violation of academic standards, such as plagiarism, cheating, or fabrication of data, which can lead to serious consequences for students and researchers. In the context of the video, academic misconduct is highlighted as a concern when discussing the results of the plagiarism checks.

💡Public domain

The public domain consists of creative works that are not protected by intellectual property laws and can be freely used by the public. These works may include texts, images, music, and other forms of content that are no longer under copyright or were never eligible for it. In the video, the user tests the plagiarism checkers with a document that is available in the public domain.


A database is an organized collection of data or information that is stored and accessed electronically. In the context of plagiarism checkers, the database refers to the vast pool of content, including web pages, academic papers, and other sources, that the tools use to compare and detect instances of plagiarism.


Grammarly offers a free plagiarism checker that claims to compare documents to 16 billion web pages.

The test document of over 2,000 words showed no plagiarism on Grammarly.

Quillbot reported a 46% match for the same document, indicating significant portions of identical content or minor changes.

Turnitin detected a 64% similarity score for the document, suggesting direct copying and paraphrasing.

Turnitin also scans the student repository, capturing university submissions where it is used.

Without the student repository, Turnitin's similarity score dropped to 53%.

Grammarly's results were inconsistent, sometimes showing no plagiarism and other times showing it.

A 100% copied text from one source was not detected as plagiarized by Grammarly on multiple attempts.

Turnitin's similarity score for the 100% copied text was 99%, indicating verbatim copying.

Quillbot found 91.2% identical content in the 100% copied text, despite it being in the public domain.

Grammarly's plagiarism checker may not pick up all instances of copied content.

Quillbot and Turnitin show differences in their sources and detection capabilities.

The sources located by Quillbot are free sources, unlike Turnitin which found the publication site.

The video provides a comparative analysis of three plagiarism checkers: Grammarly, Turnitin, and Quillbot.

The test results suggest that Grammarly's free plagiarism checker may not be as comprehensive as Turnitin or Quillbot.

For critical assessments of plagiarism, it is advised to use a more reliable and comprehensive tool than Grammarly's free checker.