Turnitin similarity score

The similarity score

The similarity score is your magic number. It tells you what percentage of your work matches sources in the plagiarism database.

Rule of thumb #1: The higher your score is, the more likely you need to address unoriginal text.

How low should my score be?



We call each snippet of text that is found in the plagiarism database a similarity. A similarity can range from a few words within a single sentence to entire paragraphs.

Rule of thumb #2: The higher the similarity, the more likely you’ve plagiarized.


Original source

Each similarity corresponds to an original source, which contains the similarity with your text.

Rule of thumb #3: The more familiar the original source looks to you, the higher the chance that you plagiarized.

Your reference list

Does your text include a reference list? Great! However, in this case, it doesn’t matter much.

We ignore your reference list, so it doesn’t influence your similarity score.

Why? Citing your sources does not constitute plagiarism.

Because many students cite their sources according to a specific citation style guide (such as APA), your references may be similar to those used by other students. These similarities are irrelevant.

The Plagiarism Checker does not index or analyze your references. We simply ignore them when comparing your text against the database.

Quoted text

Every academic writer uses quotes. Sometimes, they are necessary for expressing or analyzing your ideas. Properly quoted text does not constitute plagiarism. However, you should always follow these guidelines when quoting text:

  • Make the quote as short as possible
  • Use quotation marks or block quote
  • Properly cite the source

The Plagiarism Checker might mark quoted text as similarities. So long as the material is cited, you can ignore these similarities.

You can ignore found similarities if your quotes are properly cited.

Processing the results

Each similarity negatively influences your similarity score. This does not mean that each similarity is considered plagiarism.

You will need to decide on your own if you need to revise your work.

Step 1: Compare each similarity to the matched source

Ask yourself the following questions:

  • Does the matched source look familiar?
  • Does the memory of writing this snippet escape you?
  • If you look at the snippet, do you know why it’s marked?

It’s okay if the answer to these questions is yes. However, the more questions you can answer with yes, the more likely it is that you plagiarized and have some work to do to to address it.

Is the answer to these questions no? If so, then you can probable ignore the similarity.

Step 2: Did you intend to paraphrase or quote?

When you paraphrase, you rewrite information from a source text in your own words. You intend to make use of the source to improve the reasoning and argumentation in your own work. Paraphrased text should always be cited.

When you quote, you have literally copied the text from a source. You do so to strengthen your argument and to show the words an author has used. Quoted material should always be cited.

Step 3: Improve your writing

I want to paraphrase

If your text matches with the source, then you probably didn’t properly paraphrase the original source. You copied too much of the author’s writing.

You now have two options, depending how similar the text is:

  1. If the similarity is high and the text largely uses the wording in the original source, then it’s best to remove the text, to rewrite it entirely or to switch from paraphrasing to quoting.
  2. If the similarity is low, then you can choose to rewrite the text using more of your words. In this case, you intended to paraphrase, but you simply didn’t do enough.

Use our tips to paraphrase like a star. Always cite paraphrased text.

How do I paraphrase?

I want to quote

Cool. Don’t forget to follow the guidelines for quoting. Make 100% sure you’ve quoted correctly:

How do I quote?

Step 4: Cite, cite and cite

Finally, make sure to consistently cite your sources according to your specific citation style, whether it’s APA, Harvard or Chicago. Are you doubting whether or not you need to cite a source? Then you should probably just do it!


Ask our team

Want to contact us directly? No problem. We are always here for you.

Frequently asked questions

See all
How do I exclude irrelevant similarities from my similarity score?

Sometimes the Scribbr Plagiarism Check finds similarities that are not forms of plagiarism, such as references and correctly cited sources. You can exclude these irrelevant similarities from your total similarity score.

Exclude similarities:
Step 1: Open your Plagiarism Check results.
Step 2: Click on the highlighted similarity that you would like to exclude.
Step 3: Click on the “Exclude” button on the right.

The similarity is now excluded from your total similarity score.

If you have excluded multiple sources from your total similarity score, then you might see an error message in your Plagiarism Check results. Unfortunately, this is a problem that we cannot fix at the moment.

If you encounter this issue, you can simply ignore all irrelevant similarities and subtract their score from your total similarity score. This allows you to calculate your actual similarity score by yourself.

How can I download my Plagiarism Check results as a PDF?

Downloading a PDF of your results is simple. Just follow these two steps:

Step 1: Open your Plagiarism Check order page and click the “Generate PDF” button


Step 2: Wait until the button turns green and click “Download PDF”

Student – download PDF – 2


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.
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?

What is an acceptable percentage of plagiarism?

Your work should not contain any plagiarism. This means that even a score of 1% is too high.

However, contrary to popular belief, plagiarism checkers do not detect plagiarism, but similarities. Not all similarities found by the Scribbr Plagiarism Checker constitute plagiarism. Our check sometimes flags the following:

  • Properly cited quotes,
  • In-text citations or your reference list, and
  • Commonly used phrases that are obviously not considered plagiarism.

Because of this, you can generally follow these guidelines:

  1. A score higher than 10% is troublesome.
  2. A score between 5% and 10% it is not bad per se.
  3. A score around 5% is reasonable.

Even if your score is 1%, you will need to review each similarity and decide whether it’s necessary to revise your work.

What should I do with a found similarity?

What to do with a quote found by the check?

Sometimes a quote is found in your thesis and marked as a similarity by the Scribbr Plagiarism Checker, because the quote is also found in another source.

A quote found by our plagiarism checker is not a form of plagiarism. However, it is important that you have added a reference to this quote. Below we briefly explain the rules to write down quotes in APA Style.

Quotes of less than 40 words

When citing a section of text fewer than 40 words, you use double quotation marks directly before and directly after the quote. Next to that, you mention the author, the year and a page number.

Example: Quote of fewer than 40 words
The definition of soccer is, according to Van Persie (2014), “running back and forth with each other and whoever scores the most, wins” (p. 15).
A famous soccer player always said, “playing soccer with each other on a beautiful Sunday afternoon is the greatest thing there is” (Sneijder, 2013, pp. 2-3).

Quote of 40 words or more

If the quote contains 40 words or more, then place the quote in a separate block, which begins on a new line and is indented in its entirety.

Example: Quote of more than 40 words

The second anniversary of Scribbr was widely reported in the press:

Scribbr is now two years old and that is being celebrated with the introduction of a new version of the APA Generator. Now that more and more students make grateful use of the APA Generator, it is high time for a new version, according to the founders. The APA Generator is very popular because the APA Style has many exceptions. As a result, it is difficult for many students to really get the hang of the APA Style. In addition, the APA Generator saves many students a great deal of time (Schlagers, 2014, p. 3).

Check the article about quoting according to the APA rules for more information.

Why does the Scribbr Plagiarism Check 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

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.

Why do I see an error message in the header of my document?

No worries! This error does not influence the accuracy of your Plagiarism Check results.

If you have inserted a chapter or section title in the header of your document, then you might see an error message in your Plagiarism Check results.

Plagiarism error in header

Instead of the title, you will see an error message like the one above. Unfortunately, this is a problem that we cannot fix.

Our check may flag these error messages as similarities. You can ignore these similarities.


Why do I see “Error! Bookmark not defined” in my table of contents?

No worries! This error does not influence the accuracy of your Plagiarism Check results.

If you have an automatic table of contents and/or list of figures and tables, then you might see an error message instead of the page numbers. The error message might look like this: “Error! Bookmark not defined.”

Unfortunately, this is something we cannot fix. Our check may flag these error messages as similarities. You can ignore these similarities.

Plagiarism check - Error! bookmark not found