Turnitin (and its research-focused cousin iThenticate) generates similarity reports against massive databases and, when enabled, includes an AI-writing indicator; Blackboard’s SafeAssign, Unicheck/Urkund, Plagscan, Copyscape, Quetext, and Grammarly’s plagiarism checker offer comparable overlap detection for web sources and prior work. For AI detection specifically, services like Turnitin’s AI indicator, Originality.ai, GPTZero, and Crossplag AI Detector estimate the likelihood that text was machine-generated. All AI detectors are probabilistic—susceptible to false positives/negatives and to being fooled by heavy editing—so results should be treated as signals, not verdicts, and interpreted alongside drafting evidence (notes, version history), proper citation practice, and the course’s disclosure policy on AI use.
Turnitin now does two different things when you submit a paper:
- it generates a Similarity Report (the thing with the %), and
- it can show an AI writing indicator that estimates whether parts of a draft look machine-generated. They live side-by-side in the latest report interface but answer different questions.
1) Similarity ≠ Plagiarism
Turnitin’s updated Similarity Report (2024–2025 refresh) reorganizes matches to make them easier to read and use for feedback. It’s a formative tool that helps you check quoting, paraphrasing, and citation—not an automatic verdict of misconduct. Instructors still interpret the context.
Make the report work for you
- Quote exact lines and include citations.
- Paraphrase substantively (change structure and wording) and cite the source.
- Ask what similarity range your instructor expects for the assignment.
2) AI Writing Detection: What it Can—and Can’t—Tell You
Turnitin’s AI indicator highlights passages the model thinks may have been written by an LLM. It’s one signal, not a ruling. Turnitin itself advises that AI flags shouldn’t be the sole basis for action; instructors are urged to combine the indicator with conversation and course policy. guides.turnitin.com
Important limits
- Accuracy isn’t perfect; false positives (human text flagged as AI) and false negatives can occur.
- Detection focuses on long-form prose; it doesn’t reliably cover code, scripts, poetry, bullet lists, or very short text. g
- Turnitin regularly publishes guidance and FAQs on how to review AI scores responsibly.
3) Class ID & Enrollment Key: How You Actually Join a Class
You can’t submit anything until you’re enrolled in your instructor’s Turnitin class.
- Class ID = the numeric code Turnitin generates when a class is created.
- Enrollment Key = the case-sensitive password your instructor sets.
Students must get both directly from the instructor, then use them to self-enroll. (If a code fails, double-check the capitalization and ask your instructor to confirm the class is active.)
4) Draft Coach: Check Your Work Before You Submit
If your school turns it on, Turnitin Draft Coach lets you run similarity checks and get writing feedback in Google Docs or Microsoft Word for the web—right where you draft. Institutions pick one platform (Google or Microsoft), so use the one your campus enabled. Running a Draft Coach report helps you improve before the final upload.
5) Smart Habits for Academic Integrity
- Know your policy. Many courses now allow some AI-assisted brainstorming if you disclose it—ask what’s permitted.
- Keep artifacts. Hold onto notes, outlines, early drafts, and version history (great for demonstrating authorship).
- Cite everything. Ideas, quotes, data, even AI tools if your policy requires disclosure.
- Aim for clarity, not a magic %. A low similarity score with missing citations can still be a problem; a higher score can be fine if it’s quotations + references.
- Talk early. If a report surprises you, speak with your instructor and bring your drafting evidence.
6) Quick Troubleshooting
- No AI panel? Your institution may have it turned off.
- Can’t enroll? You need a valid Class ID and the exact Enrollment Key from your instructor.
- Want transparency features? Turnitin is shipping new report add-ons and updates throughout 2025—ask your admin what’s enabled on your campus.
The Bottom Line
Use the Similarity Report to polish your citations and paraphrasing; treat the AI indicator as a prompt for reflection and conversation—not a judgment. And remember: you’ll join your course space with a Class ID and Enrollment Key from your instructor before you can submit.
