Turnitin Similarity Report: Colors and Matches

The direct answer

A Turnitin Similarity Report shows where submitted words match sources in the databases selected for an assignment. Its percentage and color summarize the amount of matching text, not whether plagiarism happened. To interpret any result, open the highlighted passages, inspect the sources, and check how the writer quoted, paraphrased and cited them.

A score such as 67% deserves careful review because much of the submission matched, but the number alone cannot explain why. A long quoted source, a bibliography, reused assignment instructions or uncited copying can all affect the report in different ways. The surrounding text and source list matter.

How the score is calculated

Turnitin's overview of the Similarity Report defines overall similarity as matching words divided by all words in the submission. It highlights matching or highly similar text and lists the sources. Turnitin warns that a match can be a quote or cited material and does not always indicate plagiarism.

The color is a quick label for a range, not a risk grade. Turnitin's score guide gives the current color key:

These ranges are Turnitin's interface labels. The last column is editorial guidance, not a claim that any band proves misconduct or sets a universal institutional threshold. The color alone cannot tell whether the writer cited a quotation, used a template or copied without attribution.

Is 67% bad?

It is a large amount of matched text, so it calls for a close look. Start with the largest matching source. Read the highlighted passage and the surrounding sentences, then compare them with the source. Is the wording quoted and cited? Is it a shared assignment prompt? Did the student reuse earlier work that the course forbids? The answer depends on the actual passage.

Turnitin itself says its software does not check for plagiarism in writing. It checks for similarity. An instructor or institution makes the academic-integrity judgment. A lower percentage can still conceal a significant uncited passage, so there is no safe number that replaces source review.

Read a matched row step by step

1. Open the highlighted passage in the submission.
2. Open the linked source and compare the wording.
3. Check quotation marks, paraphrase and citation in the assignment's required style.
4. Look at the surrounding argument. Does the writer explain how the source supports the claim?
5. Ask whether the report's exclusions or selected databases affect the comparison.

Turnitin's report navigation guide explains how to inspect the source breakdown. If a source match looks wrong, talk to the instructor about the passage rather than changing words solely to lower the overall score.

Similarity is separate from AI writing detection

Turnitin's AI Writing Report is a different feature. It classifies qualifying text as likely AI-generated, whereas the Similarity Report compares wording with sources. An AI indicator is not a plagiarism finding, and a similarity match is not evidence that ChatGPT wrote a paragraph.

Our Turnitin overview separates the two products. The copy-and-paste guide explains why a text match does not automatically show how words entered a document. The AI detection accuracy guide covers the separate AI report and its limitations.

If you are preparing a submission, keep your source notes and drafts, cite as you write, and follow the assignment policy. The most useful goal is a clear paper whose source use you can explain, not a particular color.