How Does Turnitin Work? Turnitin Explained (2026)

Turnitin works by comparing your paper against a huge database of web pages, publications and past student papers, then scoring how much of your text matches (the similarity report) and how much looks AI-written (the AI writing report). Schools and universities use it to check originality before grading. Here is how each part works, what Turnitin is used for, and what your instructor actually sees.

What is Turnitin? (Was ist Turnitin?)

Turnitin is an academic integrity service owned by Advance Publications. It is licensed to schools, universities and publishers, and plugs into Canvas, Moodle, Blackboard, Brightspace and Microsoft Teams. Students submit through their course; instructors see the reports. In German: Turnitin ist eine Plagiats- und KI-Erkennungssoftware, die Hochschulen lizenzieren. More on the company: who owns Turnitin.

What Turnitin does, step by step

1. You submit a file through your course, or your instructor uploads it.
2. Turnitin extracts the text. It needs selectable text; scanned images are not read. See Turnitin file types.
3. Similarity check. Your text is compared with the internet, academic journals and books, and Turnitin's repository of student papers. Matches are highlighted and colour-coded by source.
4. AI writing check. For papers with 300 to 30,000 words in a supported language, Turnitin's AI model scores segments of text for AI generation, AI paraphrasing and AI humanizer use.
5. Reports are generated, usually within minutes. Your paper may be stored in the repository so future submissions are checked against it.

How Turnitin checks plagiarism

Turnitin does not decide whether you plagiarised. It shows matching text and a similarity percentage. Your instructor decides what counts. Properly quoted and cited text still matches, which is why scores are rarely 0%. Read what the similarity score means and what each percentage means.

How Turnitin's AI detection works

The AI model looks at how predictable your sentences are compared with text written by large language models. Since 27 August 2025 it also flags AI text that was modified by a humanizer. It works in English, Spanish, Japanese, Arabic, German, Dutch and Turkish; see AI detection by language and can Turnitin detect humanizers?

Turnitin rules: what your instructor controls

• Whether you can see your similarity report, and when.
• Whether you can resubmit before the deadline (resubmissions after the third wait 24 hours for a new report).
• Filters such as excluding quotes, the bibliography and small matches. See Turnitin filters and settings.
• Whether papers are stored in the repository.

The AI writing report is visible to instructors only in most setups.

See your own reports before you submit

We run your paper through Turnitin and send you both reports, the same format your instructor sees: $3.99 per document, usually within minutes, with no repository storage. If the AI report flags your writing, our editors can humanize it to 0%:

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Frequently asked questions

How does Turnitin work?

It compares your paper with web pages, publications and stored student papers to produce a similarity report, and scores the text for AI writing in a separate AI report.

What is Turnitin used for?

Schools and universities use it to check originality and AI use before grading.

Does Turnitin decide if I plagiarised?

No. It shows matches and a percentage. Your instructor decides what counts as plagiarism.

Was ist Turnitin?

Turnitin ist eine Plagiats- und KI-Erkennungssoftware, die von Hochschulen lizenziert wird.