Detection guide
Turnitin AI Detection Guide: How It Works and How to Read Your Report
What the report tells you, what it cannot prove, and what to do next.
Start by checking the report heading: AI writing and similarity are different results. A low number on one does not explain the other.
This independent guide separates Turnitin's published report guidance from the upload and delivery service offered by TurnitChecker. We are not the official Turnitin website and are not affiliated with or endorsed by Turnitin, LLC.
What does the AI report measure?
Turnitin estimates how much eligible prose appears AI-generated. It does not establish who wrote a document or prove misconduct. Poetry, code, tables and short fragments do not behave like long-form prose in this assessment.
Read the result alongside your drafts, sources and institution's rules. A model result can be wrong; do not treat it as a verdict.
Why might the highlights look different?
An August 2026 product update replaces the previous two-color English AI report with unified blue highlights. Older reports and different product versions may look different. A highlight does not reliably identify a particular AI tool.
Turnitin's interactive report instructions describe its own interface. A downloaded PDF from a reporting service is not that interface; do not expect every filter or interactive control to be available.
What do 0%, *% and a number mean?
| AI indicator | How to read it |
|---|---|
| 0% | No eligible text was flagged as likely AI-generated. This is not a certificate of human authorship. |
| *% | The estimate is in the 1–19% range. Turnitin withholds the exact score and highlights because results in this range are less reliable. |
| 20–100% | The displayed estimate relates to eligible prose, not the probability that a student cheated. |
| Unavailable or an error | An AI result is not available. Do not record it as 0%. |
How should I read the Similarity Report?
Similarity measures matching text, not AI authorship. Read the highlighted passage and its source: a quotation can match legitimately, while a small unattributed passage can still need attention. Database and exclusion settings affect what is included.
Illustration — not a customer report: a document shows *% for AI and 18% similarity. Do not add these numbers or call the document “82% original.” Review the similarity matches for quotation and citation issues; follow the AI indicator's separate guidance.
Before uploading to TurnitChecker
- Check the current upload form for accepted files and validation limits. An institutional Turnitin limit is not automatically a limit supported by our service.
- Use a document with readable text, not an image-only scan. If you paste text, check that the content is complete before submitting.
- Confirm the document language in our FAQ before purchasing. A translated website interface does not mean AI detection supports that language.
- Official software features and supplier availability can differ. Ask support if your document or required report is not covered by the current service description.
Avoid these report-reading mistakes
- Do not treat a low AI score as a guarantee that your institution will accept the work.
- Do not treat a higher-priced plan as proof of a more accurate result.
- Do not expect a pre-submission check to reproduce every result or setting in a later school or publisher submission.
- Do not pay for repeated checks simply to chase a lower number. Address the actual writing, quotation and citation issues first.
If your report is missing or seems wrong
- Confirm which report your plan includes. Standard includes AI and similarity; Academic includes an iThenticate AI report, not a separate Similarity Report.
- Check whether the report is still processing, shows *%, or is genuinely unavailable. These are different situations.
- If the document does not appear to be yours, stop sharing the report and contact support privately with the order or task reference. Do not post the document or report in a public channel.
- If processing fails, contact support before submitting repeatedly, so the task and remaining credits can be checked.
- Before final submission, keep your drafts and follow your institution's rules. Our service does not set academic pass/fail thresholds.
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