Why did the Plagiarism Check not find my copied fragment?

If you copied a fragment from a source and the Plagiarism Check did not find it, there are four possible explanations.

You paraphrased the fragment

If you paraphrased the original text by using different words and/or changing their order, the fragment will no longer be detected by the plagiarism software.

You can test this by searching the fragment in double quotation marks on Google. If no results are returned, you successfully paraphrased. Note that you still need to cite the source of the original idea.

However, if Google did return a result but our software did not highlight it, this might mean that…

The “Exclude Small Matches” number is set too high

By default, the plagiarism report shows similarities of 9 words or more. If the fragment you copied is shorter than that, it will not be shown in the report.

You can manually adjust the minimum length in order to show shorter similarities. Find out how to do that here.

Your document was not readable

If you uploaded a PDF file, it is possible that your document is not machine readable or was converted to an image instead of text. As a result, no similarities will be found.

To test if the text in your PDF is readable, you can copy and paste the document into a text editor (e.g. Microsoft Word, Notepad, TextEdit). If the text editor shows the same text as the PDF, then the text will also be readable by our plagiarism software.

If you know that you used a fragment, but it wasn’t found by our plagiarism software, it’s best to paraphrase or quote it anyway (and be sure to cite the source). It’s always better to be safe than sorry!

Frequently asked questions: Scribbr Plagiarism Checker

What is the difference between the free and premium report?

The free report tells you if your text contains potential plagiarism and other writing issues. The premium report gives you the resources you need to review issues in detail and resolve them.

Free report Premium report (from $19.95)
Plagiarism Checker

  • Plagiarism risk assessment
  • Top matching sources

Grammar Checker

  • Number of writing issues
Plagiarism Checker

  • Precise similarity percentage
  • Complete list of matching sources
  • Document view to quickly review similarities
  • Side-by-side comparison with the original text
  • Upload private documents

Grammar Checker

  • Downloadable Word document with all your writing issues corrected using Track Changes

AI Detector

  • Precise AI writing percentage
What does a “high” or “moderate” risk of plagiarism mean?

Scribbr’s free plagiarism checker estimates the risk of plagiarism by calculating the percentage of text in your document that’s similar to other sources.

A moderate or high risk of plagiarism means that the plagiarism software detected several similarities worth reviewing.

Note that similarities are not necessarily plagiarism. You will need to decide on your own whether your text needs revision or citation.

I don’t recognize a source found by the plagiarism checker. What now?

Information can often be found in more than one place. For this reason, other sources citing the same information you used can come up in your Sources Overview.

The important thing is to make sure you’ve cited the source of the material. Try to find the original source, but if you can’t find it, it’s best to cite the source where you found the information.

How accurate is Scribbr’s plagiarism checker?

Extensive testing proves that Scribbr’s plagiarism checker is one of the most accurate plagiarism checkers on the market in 2024.

The software detects everything from exact word matches to synonym swapping. It also has access to a full range of source types, including open- and restricted-access journal articles, theses and dissertations, websites, PDFs, and news articles.

Will I get a 100% match at my school if I use the Scribbr Plagiarism Checker?

No, you will never get a 100% match because the Scribbr Plagiarism Checker does not store documents in a public database.

Will my sources/document be stored in a (shared) database?

No, the Self-Plagiarism Checker does not store your document in any public database.

In addition, you can delete all your personal information and documents from the Scribbr server as soon as you’ve received your plagiarism report.

What can I do if I am not satisfied with the results of the Plagiarism Checker?

Are you not satisfied with the results of the Scribbr Plagiarism Checker, or are you experiencing difficulties with the document? Find out what to do when…

  • you cannot see your plagiarism results: Try opening the results in Google Chrome, or request a PDF copy.
  • you see an error message in the header of your document: Don’t worry – you can ignore the error message.
  • you see “Error! Bookmark not defined” in your table of contents: Don’t worry – this error doesn’t affect your results.
  • you are not satisfied with your similarity score: The similarity score shows you what percentage of your text the software found in sources in the database. That means we cannot change your score.However, you can reduce the similarities yourself by following our simple guides to interpreting the report and avoiding plagiarism. Then the similarity score of your submitted paper will be much lower. If you want to see your new score after following these guides, you can purchase a second check.
  • you are not 100% happy with our service: Read about our 100% happiness guarantee and fill in the feedback form. We will contact you within 24 hours.
Can you use the Scribbr Plagiarism Checker for free?

Yes, Scribbr offers a limited free version of its plagiarism checker. It uses the industry-leading plagiarism detection technology and has access to most content databases.

Run a free plagiarism check

What plagiarism and AI detection software does Scribbr use?

Scribbr uses advanced plagiarism detection technology similar to the software used by most universities and publishers, ensuring you receive the same or very similar results.

The add-on AI detector is powered by Scribbr’s proprietary software and is capable of detecting texts generated by ChatGPT, Perplexity and other generative AI tools with high accuracy.

To which databases will my document be compared?

Your document will be compared to the world’s largest and fastest-growing content database, containing over:

  • 99.3 billion current and historical webpages.
  • 8 million publications from more than 1,700 publishers such as Springer, IEEE, Elsevier, Wiley-Blackwell, and Taylor & Francis.
What languages are supported by the plagiarism checker?

Scribbr’s plagiarism checker offers complete support for 20 languages, including English, Spanish, German, Arabic, and Dutch. The add-on AI Detector is available for English, Spanish, German, French and Dutch texts.

The complete list of supported languages:

  • Arabic
  • Bosnian
  • Croatian
  • Czech
  • Danish
  • Dutch
  • English
  • Finnish
  • French
  • German
  • Greek
  • Italian
  • Norwegian
  • Polish
  • Portuguese
  • Russian
  • Serbian
  • Spanish
  • Swedish
  • Turkish
I ordered the Scribbr Plagiarism Checker in combination with Proofreading & Editing. When should I start the Plagiarism Checker?

If you purchased a Plagiarism Checker in combination with our Proofreading & Editing service, you can start the Plagiarism Checker anytime at your convenience.

Scribbr recommends using the Plagiarism Checker after you have received your document and gone through all of the edits. Then you can upload the most recent version of your paper and avoid having to manually transfer changes from one document to another.

Will my teacher or supervisor see my submissions to Scribbr?

No, your teacher, professor, or admissions officer will not be able to see your submissions at Scribbr because they’re not added to any shared or public databases.

Can other plagiarism checkers see my submissions to Scribbr?

Your writing stays private. Your submissions to Scribbr are not published in any public database, so no other plagiarism checker (including those used by universities) will see them.

Will Scribbr give the same result as my university’s plagiarism checker?

Scribbr uses similar plagiarism software to most universities, providing the same or very similar results.

However, universities may check your work against private student paper databases, which Scribbr can’t access, possibly leading to small differences.

To help, Scribbr offers a free Self-Plagiarism Checker add-on, allowing you to manually upload your source documents to ensure you haven’t accidentally plagiarized.

Can institutions buy plagiarism checks for a discounted price?

Yes, if you are interested in buying more than 25 plagiarism checks, please fill in this form. We will get back to you within the next two working days!

For questions, please do not hesitate to reach out to info@scribbr.com.

What do I do with a found similarity?

Review every similarity for plagiarism, and decide whether or not you need to revise your text.

  1. Review the similarity, and think about whether or not the match makes sense to you.
  2. Revise the snippet if necessary. You can do so by paraphrasing or quoting. Always cite your sources.
I uploaded the wrong document to the Scribbr Plagiarism Checker. Can I get a free new check?

If you accidentally uploaded the wrong document to the Plagiarism Checker, Scribbr will not refund you for this check or give you a discount for another check. The check starts automatically upon payment, which is why we cannot change your document anymore.

What does a similarity score of 0% mean?

A similarity score of 0% means that our plagiarism software didn’t find any similarities between your document and other documents in our database.

On average, only 1 out of 150 students achieve this. Congratulations!

What is an acceptable percentage of plagiarism?

Your work should not contain any plagiarism. Even if your score is 1%, you will need to review each similarity and decide whether it’s necessary to revise your work.

But contrary to popular belief, plagiarism checkers work by detecting similarities, not plagiarism. Not all similarities are plagiarism. Similarities can be:

  • Properly cited quotes
  • In-text citations or your reference list entries
  • Commonly used phrases

    What should I do with a found similarity?

    What does my similarity score mean?

    Your similarity score shows you what percentage of your text is found within sources in the comparison database.

    For example, if your score is 15%, then 15% of the content you wrote is unoriginal, as it matches text in the database.

    You will have to review each similarity and decide whether or not you need to revise your work.

    What is a good score? How do I update my work?

    Why can’t I see my Plagiarism Check results?

    If you’re unable to view the Plagiarism Check results in your browser, please try the following two solutions:

    1. Are you using Google Chrome?

    We’ve found that using Google Chrome resolves most issues related to the results page. First, try using Google Chrome to open your Plagiarism Check results. If you are already using Google Chrome, or if this solution does not work, then proceed to the second solution.

    2. Contact support for a PDF copy of the results.

    If the first solution doesn’t work, you can contact our support team via chat or email and request a PDF copy of the results via email. This way, you can still review and process the results. We apologize for the inconvenience.

    Can I check my document for plagiarism more than once?

    Scribbr checks your document for plagiarism only once. You can use the “exclude text” feature to exclude similarities that you’ve resolved, which automatically updates your similarity score.

    If you would like to recheck your entire document, you can purchase a new plagiarism check at the regular price. We don’t currently offer a subscription service.

    What should I do with a quote found by the check?

    Sometimes a quote is marked as a similarity by the Scribbr Plagiarism Checker. A quote is not a form of plagiarism, but you do have to ensure you have properly cited the original source.

    If you’re certain that you have correctly quoted and cited, you can exclude the similarity from your plagiarism score.

    Below we briefly explain the rules for quoting in APA Style.

    Quotes under 40 words

    When quoting fewer than 40 words, use double quotation marks around the quote, and provide an APA in-text citation that includes the author, the year, and a page number or range.

    Horváth and Kovács (2020) argue that plagiarism is often a matter of confusion rather than deception” (p. 4).
    A recent study of student plagiarism found that plagiarism is often a matter of confusion rather than deception (Horváth & Kovács, 2020, p. 4).

    Quotes over 40 words

    If the quote contains 40 words or more, format it as a block quote, which begins on a new line and is indented in its entirety. Include an in-text citation after the period.

    Sometimes it is necessary to quote a source at length:

    Block quoting is particularly useful when you want to comment on an author’s language or present an argument that you will then critique. By setting the quote on a new line and indenting it, the passage is clearly marked apart from your own words. Therefore, no quotation marks are necessary. (O’Connor, 2019, p. 38)
    Why does the Scribbr Plagiarism Checker regard a source in my reference list as a similarity?

    The Scribbr Plagiarism Checker detect similarities between your paper and a comprehensive database of web and publication content. Because many students write their references in the same way (for instance in APA Style), a plagiarism checker finds many similarities with these sources.

    A reference found by the check is not a form of plagiarism. Therefore, there is no need to take action.

    How to exclude your reference list from your results:

    You can exclude matches from your reference list in your Plagiarism Check results. However, please be aware that this might not always work, depending on your document.

    Step 1: Open your Plagiarism Check results.
    Step 2: Click the settings button in the “Sources overview” (see picture below).
    Step 3: Select exclude reference list (see picture below).
    Step 4: Click “Done.”
    Step 1 - Deselect Reference list

    Step 2 - Deselect Reference list

    Which file formats are supported by the Scribbr Plagiarism Checker?

    The Scribbr Plagiarism Checker is able to work with the following file formats:

    • Doc
    • Docx
    • Pdf
    • Odt

    The format you use doesn’t influence the final result. If you’re working with a format not listed here, we recommend converting it prior to submitting.

    Can I buy a monthly subscription for the Scribbr Plagiarism Checker?

    At the moment we do not offer a monthly subscription for the Scribbr Plagiarism Checker. This means you won’t be charged on a recurring basis – you only pay for what you use. We believe this provides you with the flexibility to use our service as frequently or infrequently as you need, without being tied to a contract or recurring fee structure.

    You can find an overview of the prices per document here:

    Small document (up to 7,500 words) $19.95
    Normal document (7,500-50,000 words) $29.95
    Large document (50,000+ words) $39.95

    Please note that we can’t give refunds if you bought the plagiarism check thinking it was a subscription service as communication around this policy is clear throughout the order process.

    Scribbr Plagiarism Checker