What Is a Good Turnitin Score? Is 15%, 20% or 30% Too High?
A good Turnitin similarity score is under 15%, and under 20% is usually fine. See what 4%, 12%, 16%, 20% and 30% mean and when a score is too high.
A good Turnitin score for most essays and research papers is under 15%, and a similarity score under 20% is usually acceptable when the matches come from many different sources. Turnitin doesn't set a pass mark of its own. Your school or instructor decides what an acceptable Turnitin score is, and they read the report to see what the matching text is.
A 25% score made up of cited quotes and reference list entries can be normal for a literature review. A 12% score where most of the match comes from one website is a bigger concern, because it points to a passage copied or paraphrased too closely. Both the total and the biggest single source matter.
What is Turnitin and what does its score measure?
Turnitin is a text-matching service that schools and universities use to check student work. It was founded in 1999, and instructors usually connect it to the course page you submit through, such as Canvas, Moodle or Blackboard. When you submit, Turnitin compares your text with web pages, published papers and earlier student submissions, then builds a Similarity Report.
The similarity score is the share of your text that matches something in those databases. Your instructor picks which databases each assignment checks against. In Turnitin's words, the percentage "reflects how much a student's work matches other content in Turnitin's databases that the instructor selects for the assignment."
The score counts matching text whatever the reason for the match. A quote in quotation marks with a correct citation still counts. So does a reference list entry formatted the same way as in other papers, and a common phrase like "the results suggest that". Turnitin's guide on Turnitin and plagiarism says plagiarism "cannot be determined by the similarity score alone."
The newer version of the report sorts every match into one of four groups, based on whether it has an in-text citation and quotation marks. Your instructor can quickly see which matches are cited quotes and which are uncited text. A high score made mostly of cited material is easy to explain this way.
Turnitin also gives a separate AI writing score, which estimates how much of the text an AI tool may have written. It's calculated independently and doesn't change your similarity score.
Acceptable Turnitin score ranges, with Turnitin's colors
Turnitin shows each similarity score with a colored icon. Its guide to understanding the similarity score lists five color bands. Blue means no matching text, and green means one word up to 24%. Yellow is 25% to 49%, orange is 50% to 74% and red is 75% to 100%. Turnitin notes that the colors can look different in some learning platforms, and the results stay the same.
The colors aren't grades. Green covers everything from 1% to 24%, so a green icon can still include one copied paragraph. A yellow icon can be fine for a literature review full of cited quotes. As a rough guide for an essay or research paper:
| Similarity score | Turnitin color | What it usually means | What to do |
|---|---|---|---|
| 0% | Blue | No matching text found | Nothing |
| 1% to 15% | Green | Normal overlap from references, quotes and common phrases | Nothing in most cases |
| 16% to 24% | Green | Usually fine if the matches are spread across many sources | Check the biggest single source |
| 25% to 49% | Yellow | High for an essay, normal for some quote-heavy papers | Review every large match |
| 50% to 74% | Orange | Large parts of the paper match other work | Rewrite the matched sections before you submit |
| 75% to 100% | Red | Most of the paper matches, sometimes an earlier upload of the same paper | Ask your instructor to check for your earlier submission |
Turnitin's guide refers to "the acceptable score set by their institution", because every school sets its own limit. If your course handbook or graduate school gives a number, that number is the one that applies to you. If it doesn't, ask your instructor before you submit.
Look at the biggest single source as well as the total. Twenty sources at 1% each usually means references, set phrases and cited quotes. One source at 10% usually means a passage that stayed too close to its original wording, and that passage is worth fixing even when the total looks low.
Is 10%, 15%, 20% or 30% similarity on Turnitin bad?
No, a 10% or 15% Turnitin score isn't bad, and 20% is usually acceptable. A score of 30% is high for most essays, so read the report and fix the large matches before you submit. For a typical essay or research paper:
| Score | Is it bad? | What to check |
|---|---|---|
| 4% to 5% | No, this is low for any paper with citations | Nothing |
| 8% to 12% | No, this is typical overlap from references and set phrases | Only a single source with most of the match |
| 14% to 18% | Usually not, as long as no single source stands out | The biggest single source |
| 20% | Usually acceptable, at the top of the normal range | Quotes and paraphrased passages |
| 25% to 28% | High for an essay, normal for some literature reviews | Every match above 2% |
| 30% to 34% | High, and your instructor is likely to read the report closely | Paraphrases that follow the source too closely |
| 40% and above | Very high for your own writing | Each matched section, rewritten from your notes |
The type of paper changes what's normal. Turnitin says longer assignments tend to have higher scores because there's more text to match. It also lists research writing and argumentative essays as genres where some similarity is expected, and reflective or creative writing as genres where it isn't. So 18% is ordinary for a 6,000-word literature review and high for a 1,000-word reflective essay.
Theses and dissertations follow your graduate school's policy. Some schools set a lower limit than for coursework, and some apply the limit with the reference list excluded. The policy is usually in the thesis submission guidelines, and your supervisor will know it.
Why is my Turnitin score so high?
Your Turnitin score is usually high because of cited quotes, your reference list, common academic phrases or an earlier draft of the same paper. Each of these counts as matching text even when you've done nothing wrong. Turnitin's guide says research papers and literature reviews with many quotes and citations "will naturally yield higher scores."
Your reference list
Reference list entries follow set formats, so the same entry in APA or Harvard style appears in many other papers. A long bibliography can add several percentage points to the total. Instructors can exclude the bibliography with a filter, and not every assignment has that filter turned on.
Quotes, even when you cite them
A direct quote uses the exact words of its source, so Turnitin counts it as a match. The quotation marks and citation show your instructor that you used it correctly, and the report groups it with the cited and quoted matches. Instructors can also exclude quotes from the score.
Turnitin gives the example of a student whose qualitative study scored 53% because it had many quotes and a long bibliography, as the topic required. That was over the school's limit. Turnitin says the problem would have been avoided if the quotes and bibliography had been excluded from the report.
An earlier draft of the same paper
If you submitted a draft through Turnitin and then the final version, the final can match your own draft. Turnitin's guide describes a student whose final draft scored 100% for this reason. The instructor fixed it by excluding the student's previous submissions from the report. If your score jumps after a resubmission, tell your instructor.
Your name, title page and assignment template
Your name, student number, course title and any template text from the assignment can match earlier submissions. Turnitin suggests that instructors exclude small matches, and says excluding matches under 10 words usually removes a student's name. Template headings that every student was given match each other in the same way.
Common phrases and methods wording
Phrases like "the results indicate that" and "further research is needed" appear in thousands of papers. Methods sections that describe a standard procedure also use fixed wording. These matches are short and spread across many sources, so each one adds very little to the total.
What does a 0% Turnitin score mean?
A 0% Turnitin score means Turnitin found no text in your paper that matches its databases. Turnitin says a 0% similarity score is rare for long assignments with quotes, because a cited quote from a source in its database should show up as a match. If there are no Integrity Flags and no AI writing was detected, Turnitin says the 0% may mean the paper is entirely original.
Integrity Flags are warnings in the newer report for text that looks altered to avoid matching. Turnitin checks documents of at least 500 characters for two kinds of flag. One is hidden text, such as white characters or hidden quotation marks. The other is replaced characters, which are letters from other alphabets that look like normal ones. A flag tells your instructor to look at that part of the paper more closely.
A 0% score isn't a problem in itself. It's more likely on short assignments, reflective writing and papers without direct quotes. A paper with a full reference list and several quotes usually scores above 0%, unless the instructor excluded quotes and the bibliography.
Lower a high similarity score
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Try the Paraphrasing ToolWhat research says about Turnitin's similarity checks
A team of researchers from seven countries, led by Tomáš Foltýnek, tested 15 text-matching systems in a 2020 study in the International Journal of Educational Technology in Higher Education. Turnitin was one of them. The test documents were in eight languages and included copied text, text with words swapped for synonyms, manual paraphrases and translations. The team also added original documents to see whether the systems flagged text that wasn't copied.
Turnitin found the most open-access papers of all the systems. It was also one of three systems, with Urkund and PlagiarismCheck.org, that gave promising results on text where words had been swapped for synonyms. On manually paraphrased text, no system did well, although Turnitin was in the group that did somewhat better. Only one system, Akademia, detected translated text.
The authors rated Turnitin "partially useful", along with PlagAware, PlagScan, StrikePlagiarism.com and Urkund. No system reached their top rating of "useful". They also found that the systems sometimes marked original material as problematic. The test left out paywalled publisher content, because Turnitin has exclusive access to publisher databases and the team wanted a fair comparison.
The study's main point matches Turnitin's own advice. The authors write that software "cannot determine plagiarism". It can help a person find text similarity that may be plagiarism. For you, it means your instructor uses the score as a first step. They read the matched passages and decide what they mean.
The Turnitin AI score is a separate number
Turnitin's AI score is a separate percentage that estimates how much of your qualifying text an AI tool may have written. Turnitin says it's "different from and independent of the similarity score", and AI highlights don't appear in the Similarity Report. Lowering one number doesn't change the other.
The AI score only counts qualifying text, which Turnitin defines as prose sentences in long-form writing such as essays, dissertations and articles. It doesn't score bullet points, tables, poetry, code or annotated bibliographies. Your file needs at least 300 words of prose and no more than 30,000 words, in English, Spanish, Japanese or Arabic. Turnitin's guide to the AI Writing Report lists the results your instructor can see:
| What the report shows | What it means |
|---|---|
| 0% | No qualifying text was flagged as AI-generated |
| *% (asterisk) | A score from 1% to 19%, hidden because Turnitin found more false positives in that range |
| 20% to 100% | The share of qualifying text flagged as likely AI-generated, or AI-generated and then changed with a paraphrasing tool |
| File didn't meet the requirements | Too short, too long, or an unsupported language or file type |
Turnitin started showing the asterisk for low scores on July 8, 2024, so older reports can still show a number below 20%. The English detector also looks for AI text that was reworded by a paraphrasing tool or a bypasser tool. Turnitin says its model "may not always be accurate" and shouldn't be the only basis for action against a student.
Turnitin doesn't publish an acceptable AI score. A hidden score under 20% gives your instructor no percentage to act on. Above 20%, your school's AI policy decides what happens next. Our guide to Turnitin Clarity explains how schools set those policy tiers.
Independent tests show the limits of the AI score too. In a 2024 study in the Journal of Academic Ethics, Mike Perkins and colleagues wrote 22 test submissions with ChatGPT (GPT-4), using prompts designed to make detection harder. Turnitin flagged 91% of the submissions as containing AI-generated content, and it identified 54.8% of the AI-written text in them. When 15 staff members marked the papers alongside real student work, they reported 54.5% of the test submissions for academic misconduct.
If you're worried about a high AI score on your own writing, our guide to lowering a Turnitin AI score responsibly covers what to do. If your school allows AI help with drafts, our academic AI humanizer rewrites AI-assisted text in a natural academic style. It keeps your citations and technical terms.
How to lower a high Turnitin score before you submit
To lower a high Turnitin similarity score, rewrite the passages that follow one source too closely and quote exact wording with a citation. Then ask your instructor about the quote and bibliography filters. Work through the report in this order:
- Open the report and look at the source list. Fix the biggest single sources first, because one or two close paraphrases often account for most of a high score.
- Rewrite close paraphrases from your notes. Read the source, close it, write the idea in your own sentence structure, then add the citation. Swapping a few words keeps the original sentence shape, and Turnitin still matches it.
- Use quotation marks for any wording you keep exactly. A sentence that's half quoted and half reworded still matches, and it won't show up as a cited quote.
- Cut the quotes you don't need. A summary in your own words with a citation usually makes the same point and adds less matching text.
- Check for an earlier upload. If you submitted a draft before, ask your instructor to exclude your previous submissions.
- Ask about the filters. Your instructor can exclude quotes, the bibliography and small matches, and Turnitin's own examples show these settings fixing scores raised by quotes and references.
Students usually can't run Turnitin themselves. Some instructors set up a draft assignment so you can see your report before the deadline, and it's worth using if yours does. Our guides on how to read a Turnitin similarity report and how to paraphrase without plagiarism go through the report and the rewriting step in more detail. For a full checklist, see how to reduce your Turnitin similarity score.
If you need help rewording a passage, our paraphrasing tool for academic writing gives you new wording and structure while keeping citations and technical terms in place. Edit each result so it matches your own voice, and cite the original idea as usual.
Frequently asked questions
Q: What is a good Turnitin score for a research paper?
A good Turnitin score for a research paper is usually under 15%. Up to about 24% is often fine when the matches are cited quotes, references and common phrases from many sources. Research papers match more text than reflective essays because they quote and cite more. Your school's policy sets the limit that applies to you.
Q: Is 25% on Turnitin bad?
A 25% Turnitin score is high for an essay but can be normal for a literature review or a quote-heavy paper. It's the point where Turnitin's color changes from green to yellow. Check whether the matches are cited quotes and references or uncited passages from one or two sources, and rewrite the uncited ones.
Q: What Turnitin score is acceptable for a thesis or dissertation?
The acceptable Turnitin score for a thesis or dissertation is set by your graduate school, and it can be lower than for coursework. Some schools apply the limit with the reference list excluded. Check the thesis submission guidelines or ask your supervisor before the final upload.
Q: Does a high Turnitin score mean I plagiarized?
No, a high Turnitin score doesn't mean you plagiarized. Turnitin says plagiarism can't be determined by the similarity score alone. Cited quotes, a long reference list and earlier drafts of your own paper all add to the score. Your instructor looks at the matches to decide what they mean.
Q: Do quotes and references count in the Turnitin score?
Yes, quotes and references count in the Turnitin score unless your instructor excludes them. Turnitin has filters for quotes, the bibliography and small matches. The newer report also groups matches by whether they have quotation marks and in-text citations, so cited quotes are easy to tell apart.
Q: Can I check my Turnitin score before I submit?
You can check your Turnitin score before the final deadline only if your instructor sets up a draft or practice assignment. Students can't usually run Turnitin on their own. If there's no draft option, review your quotes, paraphrases and reference list yourself before you submit.
Q: Does Turnitin show which sources you matched?
Yes, Turnitin's Similarity Report lists every matched source with the share of your paper that matches it. Your instructor sees the same list and the highlighted passages. That's why the biggest single source often matters more than the total score.
Q: What AI score is acceptable on Turnitin?
Turnitin doesn't publish an acceptable AI score. Scores from 1% to 19% show only as an asterisk, because Turnitin found more false positives in that range. Above 20%, your school's AI policy decides what happens, and Turnitin says the score shouldn't be the only basis for action.
Q: Can Turnitin detect paraphrasing?
Yes, Turnitin can detect paraphrasing that keeps the original sentence structure or swaps in synonyms. In a 2020 test of 15 systems, Turnitin was among the better ones on synonym-swapped text. Its English AI detector also looks for text reworded by AI paraphrasing tools, and a paraphrase without a citation is still plagiarism whatever the score.
Rewrite close paraphrases in your own structure while keeping citations and technical terms. Included from the Academic plan.
Lisa holds a PhD in linguistics from NYU, and has always been curious about how computers can leverage applied linguistics to understand and communicate in human language and assist with editing human written content. She is currently the Chief Marketing Officer at ProofreaderPro, where she leads marketing across copy, social media, email, and offline channels.
