Turnitin's AI writing detection capabilities FAQs

How do Turnitin’s AI writing detection capabilities work?

Does Turnitin offer a solution to detect AI writing?

Yes. Turnitin's AI writing detection capabilities empower educators, researchers, publishers, and other users to identify content generated by AI writing tools such as ChatGPT. Furthermore, it can also identify instances where AI-generated text may have been modified by AI paraphraser or bypasser (also called humanizers) tools to evade detection.

We have added an AI writing indicator to the Similarity Report. It shows an overall percentage of the document that AI writing tools or large language models may have generated or modified. The indicator further links to a report that highlights the text segments that our model predicts were written or modified by an AI tool. Please note, only instructors and administrators are able to see the indicator.

While Turnitin has confidence in its model, Turnitin does not make a determination of misconduct; rather, it provides data for the educators to make an informed decision based on their academic and institutional policies. Hence, we must emphasize that the percentage on the AI writing indicator should not be used as the sole basis for action or a definitive grading measure by instructors.

How does it work?

When a paper is submitted to Turnitin, sentences from the submission are extracted and segmented into overlapping sections for prediction analysis. Each segment is classified by the AI detection model and given a value between 0 and 1, denoting the probability of the text being likely human or AI-generated. Each qualifying sentence within these segments inherits the segment’s score. Since segments overlap, some sentences may have multiple scores, which are then pooled into a single score. These sentence scores are further aggregated and used to compute the overall document AI writing score. 

Currently, Turnitin’s AI writing detection model for English submissions can detect content from GPT-4o (released 2024-05), GPT-4o-mini (released 2024-07), GPT-5 (released 2025-08), GPT-5-mini (released 2025-08), GPT-5-nano (released 2025-08), GPT-5.1 (released 2025-11), GPT-5.2 (released 2025-12), GPT-5.2-pro (released 2025-12), GPT-5.3 (released 2026-02), GPT-5.4 (released 2026-03), GPT-5.4-pro (released 2026-03), o1-mini (released 2024-09), Gemini-1.0- pro (released 2023-12), Gemini-1.5- pro (released 2024-02), Gemini-2.5-pro (released 2025-03), Gemini 2.5 Flash (released 2024-03), Gemini-3-flash-preview (released 2025-12), Gemini-3-pro-preview (released 2025-11), Gemini-3.1-pro-preview (released 2026-02), Claude-3-Haiku (released 2024-03), Claude Sonnet-3.5 (released 2024-06), Claude Sonnet-3.7 (released 2025-02), Claude Sonnet-4.5 (released 2025-09), Claude Sonnet-4.6 (released 2026-02), Claude-Haiku-4.5 (released 2025-10), Claude-Opus- 4.5 (released 2025-11),  LLaMA-3.3 (released 2024-12), LLaMA-4-Maverick (released 2025-04), Mistral-Large-3 (released 2025-05), Deepseek-v3.2 (released 2025-12), Nova-2-lite (released 2025-12), Grok-4.1 (released 2025-11), and tools based on these LLMs as well. We will continue to expand our detection capabilities to other models in the future.

What parameters or flags does Turnitin’s model take into account when detecting AI writing?

Large language models (LLMs) are trained on the text of the entire internet, and they are essentially taking that large amount of text and generating sequences of words based on picking the next highly probable words. This means that GPT-3 and ChatGPT tend to generate the next word in a sequence of words in a consistent and highly probable fashion. Human writing, on the other hand, tends to be inconsistent and idiosyncratic, resulting in a low probability of picking the next word the human will use in the sequence. 

Our classifiers are trained to detect these differences in word probability and are adept at the particular word probability sequences of human writers.

How was Turnitin’s model trained?

Our model is trained on a representative sample of data spread over a period of time, that includes both AI generated and authentic academic writing across geographies and subject areas. While creating our sample dataset, we also took into account statistically under-represented groups like second-language learners, English users from non-English speaking countries, students at colleges and universities with diverse enrollments, and less common subject areas such as anthropology, geology, sociology, and others to minimize bias when training our model.

Can I check past submitted assignments for AI writing?

Yes. Previously submitted assignments can be checked for AI writing detection if they’re re-submitted to Turnitin and if you have AI writing enabled for your account.

What languages are supported?

Turnitin’s AI writing detection capabilities are able to detect likely AI-generated content for documents submitted in long-form English, long-form Spanish and long-form Japanese. However, our AI paraphrasing and bypassing detection capabilities are only available for English submissions.

What will happen if a paper in a non-supported language is submitted?

If a paper in a non-supported language is submitted, the detector will not process the submission. The indicator will show an empty/error state with ‘in-app’ guidance that will tell users that this capability only works for supported languages. No report will be generated if the submitted content is not in one of the supported languages.

Can I or my admin suppress the new indicator and report if we do not want to see it?

Yes, admins have the option to enable/disable the AI writing feature from their admin settings page. Disabling the feature will remove the AI writing indicator & report from the Similarity report and it won’t be visible to instructors and admins until they enable it again.

Will the addition of Turnitin’s AI detection functionality to the Similarity report change my workflow or the way I use the Similarity report?

No. This additional functionality does not change the way you use the Similarity report or your existing workflows. Our AI detection capabilities have been added to the Similarity report to provide a seamless experience for our customers.

Will the AI detection capabilities be available via LMSs such as Moodle, Blackboard, Canvas, etc?

Yes, users will be able to see the indicator and the report via the LMS they’re using. We have made AI writing detection available via the Similarity report. There is no AI writing indicator or score embedded directly in the LMS user interface and users will need to go into the report to see the AI score.

Does the MS Teams integration support the AI writing detection feature?

AI writing detection is only available to instructors using the Microsoft Teams integration with Turnitin Feedback Studio. AI writing detection is not available for customers using the Microsoft Teams Assignment Similarity integration, as it only uses the student viewer. There is no separate teacher viewer. And since our AI detection capability is only going to be available to educators, we cannot provide it via MS Teams.

However, if an instructor using the Similarity integration has a concern that a report may have been written with an AI writing tool, they can request that their administrator use the submission search tool to view a full report. 

How is authorship detection within Originality different from AI writing detection?

Turnitin’s AI writing detection technology is different from the technology used within Authorship (Originality). Our AI writing detection model calculates the overall percentage of text in the submitted document that was likely generated by an AI writing tool. Authorship, on the other hand, uses metadata as well as forensic language analysis to detect if the submitted assignment was written by someone other than the student. It will not be able to indicate if it was AI written; only that the content is not the student’s own work.

AI detection results & interpretation

What does the percentage in the AI writing detection indicator mean?

The percentage indicates the amount of qualifying text within the submission that Turnitin’s AI writing detection model determines was likely generated by AI or likely generated and modified by an AI paraphraser or bypasser. This qualifying text includes only prose sentences, meaning that we only analyze blocks of text that are written in standard grammatical sentences and do not include other types of writing such as lists, bullet points (short non-sentence structures), or other non-sentence structures.

This percentage is not necessarily the percentage of the entire submission. If text within the submission is not considered long-form prose text, it will not be included.

What do the different colors in the report mean?

The percentage detected as AI is the total amount of qualifying text in the submission likely originated from a Large Language Model (LLM). Likely AI-generated text, including text likely modified by a bypasser, is highlighted in cyan in the submission.

What is the accuracy of Turnitin’s AI writing indicator?

We strive to maximize the effectiveness of our detector while keeping our false positive rate - incorrectly identifying fully human-written text as AI-generated - under 1% for documents with over 20% of AI writing. In other words, we might flag a human-written document as AI-written for one out of every 100 fully-human written documents. 

To bolster our testing framework and diagnose statistical trends of false positives, before every update or new model release, we perform tests on over 700,000 additional academic papers that were written before the release of ChatGPT to further validate our less than 1% false positive rate.

In order to maintain this low rate of 1% for false positives, there is a chance that we might miss some AI written text in a document. We’re comfortable with that since we do not want to incorrectly highlight human-written text as AI-written. For example, if we identify that 50% of a document is likely written by an AI tool, it could contain as much as 65% AI writing.

We’re committed to safeguarding the interests of students while helping institutions maintain high standards of academic integrity. We will continue to adapt and optimize our model based on our learnings from real-world document submissions, and as large language models evolve to ensure we maintain this less than 1% false positive rate.

How does Turnitin ensure that the false positive rate for a document remains less than 1%?

Before we release any updates to our existing model or launch a new model, we perform additional tests on 700,000 additional academic papers that were written before the release of ChatGPT to further validate our less than 1% false positive rate. Based on the results of these tests, we make updates to our model to ensure we hold steadfast on our objective of keeping our false positive rate below 1% for a document.

The percentage shown sometimes doesn’t match the amount of text highlighted. Why is that?

Unlike our Similarity Report, the AI writing percentage does not necessarily correlate to the amount of text in the submission. Turnitin’s AI writing detection model only looks for prose sentences contained in long-form writing. Prose text contained in long-form writing means individual sentences contained in paragraphs that make up a longer piece of written work, such as an essay, a dissertation, or an article, etc. The model does not reliably detect AI-generated text in the form of non-prose, or code, nor does it detect short-form/unconventional writing such as bullet points (short non-sentence structures).

This means that a document containing several different writing types would result in a disparity between the percentage and the highlights.

What do the different indicators mean?

Upon opening the Similarity Report, after a short period of processing, the AI writing detection indicator will show one of the following:

• Blue with a percentage between 0 and 100: The submission has processed successfully. The displayed percentage indicates the amount of qualifying text within the submission that was only likely AI-generated or bypassed, and likely AI-generated text that was also likely AI-paraphrased. As noted previously, this percentage is not necessarily the percentage of the entire submission. If text within the submission is not considered long-form prose text, it will not be included. 
   
• Low percentage (*%): False positives (incorrectly flagging human-written text as AI-generated) are a possibility in AI models. To avoid potential incidence of false positives, no score or highlights are attributed for AI detection scores in the 1% to 19% range. When AI is detected below the 20% threshold in the report, it is now indicated with an asterisk (*%) and no percentage is attributed. 
   
• Gray with no percentage displayed (- -): The AI writing detection indicator is unable to process this submission. This can be due to one, or several, of the following reasons:
  • The submission was made before the release of Turnitin’s AI writing detection capabilities. The only way to see the AI writing detection indicator/report on historical submissions is to resubmit them.
    • The submission does not meet the file requirements needed to successfully process it for AI writing detection. In order for a submission to generate an AI writing report and percentage, the following requirements must be met for English-language submissions:
      • File size must be less than 100 MB
      • File must have at least 300 words of prose text in a long-form writing format
      • Files must not exceed 30,000 words 
      • File must be written in English
      • Accepted file types: .docx, .pdf, .txt, .rtf

Note: For details on technical requirements for Spanish or Japanese submissions, please refer to the Japanese FAQ and Spanish FAQ pages.

Best practice: When using Turnitin's AI writing detection for assignments, it's best practice to have all students submit their work in the same file format (e.g., all .docx or all .pdf). This helps maintain uniformity in how submissions are processed.

• Error ( ! ): This error means that Turnitin has failed to process the submission.  Turnitin is constantly working to improve its service, but unfortunately, events like this can occur. Please try again later. If the file meets all the file requirements stated above, and this error state still shows, please get in touch through our support center so we can investigate for you.

What can I do if I feel that the AI writing detection indicator is incorrect? How does Turnitin’s indicator address false positives?

If you find AI written documents that we've missed, or notice authentic student work that we've predicted as AI-generated, please let us know! Your feedback is crucial in enabling us to improve our technology further. You can provide feedback via the 'feedback' button found in the AI writing report. While using the new, enhanced report experience, simply click or tap the Turnitin logo in the bottom right corner of the viewer and select Give feedback.

Sometimes false positives (incorrectly flagging human-written text as AI-generated), can include content without a lot of structural variation, text that literally repeats itself, or text that has been paraphrased without developing new ideas. If our indicator shows a higher amount of AI writing in such text, we advise you to take that into consideration when looking at the percentage indicated.

In a longer document with a mix of authentic writing and AI generated text, it can be difficult to exactly determine where the AI writing begins and original writing ends, but our model should give you a reliable guide to start conversations with the submitting student.

In shorter documents where there are only a few hundred words, the prediction will be mostly "all or nothing" because we're predicting on a single segment without the opportunity to overlap. This means that some text that is a mix of AI-generated and original content could be flagged as entirely AI-generated.

Please consider these points as you are reviewing the data and following up with students or others.

Will students be able to see the results?

The AI writing detection indicator and report are not visible to students. However, with the PDF download feature, instructors can download and share the AI report with students.

Does the AI Indicator automatically feed a student’s paper into a repository?

No, it does not. There is no separate repository for AI writing detection, and customers retain the ability to choose whether to add their student papers into the repository or not. Our AI writing detection capabilities are part of our existing Similarity Report workflow. For institutions that have the AI writing feature enabled, when we receive submissions, they are compared and evaluated via our proprietary algorithms for both similarity text matching and the likelihood of being likely AI writing (generated by LLMs).

If enabled, AI writing detection is run on a submission and the results are shared on the similarity report. Results regarding the percentage AI writing identified by the detector, along with the segments identified highly likely written by AI – are retained as part of the similarity report.

What is the difference between the Similarity score and the AI writing detection percentage? Are the two completely separate or do they influence each other?

The Similarity score and the AI writing detection percentage are completely independent and do not influence each other. The Similarity score indicates the percentage of matching-text found in the submitted document when compared to Turnitin’s comprehensive collection of content for similarity checking.

The AI writing detection percentage, on the other hand, shows the overall percentage of text in a submission that Turnitin’s AI writing detection model predicts was generated or modified by AI writing tools.

Does the Turnitin model take into account that AI writing detection technology might be biased against particular subject-areas or second language writers?

Yes, it does. One of the guiding principles of our company and of our AI team has been to minimize the risk of harm to students, especially those disadvantaged or disenfranchised by the history and structure of our society. Hence, while creating our sample dataset, we took into account statistically under-represented groups like second-language learners, English users from non-English speaking countries, students at colleges and universities with diverse enrollments and less common subject areas such as anthropology, geology, sociology, and others.

How can I use the AI writing detection indicator percentage in the classroom with students?

Turnitin’s AI detection indicator shows the percentage of text that was likely generated or modified by an AI writing tool while the report highlights the exact segments that seem to be AI-written or AI-modified. The final decision on whether any misconduct has occurred rests with the reviewer/instructor. Turnitin does not make a determination of misconduct, rather it provides data for the educators to make an informed decision based on their academic and institutional policies.

Can I download the AI report like the Similarity report?

Yes. The AI detection report can be downloaded as a PDF via the ‘download’ button located in the right-hand corner of the report.

Can I view aggregated AI scores across submissions for my institution?

Yes, starting February 13 2024, administrators can view aggregated AI scores for their institution. This feature is currently only available to admins and shows statistics at the institution/parent level. As we continue to develop this functionality further, we will update you.

Scope of detection

Which AI writing models can Turnitin’s technology detect?

Currently, Turnitin’s AI writing detection model for English submissions can detect content from GPT-4o (released 2024-05), GPT-4o-mini (released 2024-07), GPT-5 (released 2025-08), GPT-5-mini (released 2025-08), GPT-5-nano (released 2025-08), GPT-5.1 (released 2025-11), GPT-5.2 (released 2025-12), GPT-5.2-pro (released 2025-12), GPT-5.3 (released 2026-02), GPT-5.4 (released 2026-03), GPT-5.4-pro (released 2026-03), o1-mini (released 2024-12), Gemini-1.0- pro (released 2023-12), Gemini-1.5- pro (released 2024-02), Gemini-2.5-pro (released 2025-03), Gemini 2.5 Flash (released 2024-03), Gemini-3-flash-preview (released 2025-12), Gemini-3-pro-preview (released 2025-11), Gemini-3.1-pro-preview (released 2026-02), Claude-3-Haiku (released 2024-03), Claude Sonnet-3.5 (released 2024-06), Claude Sonnet-3.7 (released 2025-02), Claude Sonnet-4.5 (released 2025-09), Claude Sonnet-4.6 (released 2026-05), Claude-Haiku-4.5 (released 2025-10), Claude-Opus- 4.5 (released 2025-11),  LLaMA-3.3 (released 2024-12), LLaMA-4-Maverick (released 2025-04), Mistral-Large-3 (released 2025-05), Deepseek-v3.2 (released 2025-12), Nova-2-lite (released 2025-12), Grok-4.1 (released 2025-11), and tools based on these LLMs as well. We will continue to expand our detection capabilities to other models in the future.

Which model is Turnitin’s AI detection based on?

Our current system uses a modern deep learning approach based on the transformer architecture. We selected this approach because transformer-based models have demonstrated strong performance across a wide range of language tasks and form the basis of many leading contemporary AI systems. That said, we do not rely solely on off-the-shelf transformer architecture. Instead, we continuously improve the architecture, incorporating advances from our own research lab as well as from the broader deep learning research community. More importantly, our models are also trained on our vast inhouse corpus of academic data. While our current system is transformer-based, we may adopt other deep learning architectures in the future if they provide meaningful improvements.

This approach differs from classical AI methods, which often depend on hand-crafted rules or manually defined features. Our model is not explicitly programmed to evaluate specific signals such as “burstiness,” “perplexity,” or other individual metrics sometimes referenced in public discussions. Instead, it learns statistical patterns from our training data. As a result, its outputs are generated by many learned patterns working together rather than by a small set of transparent, human-readable rules. For that reason, individual predictions may not always be explainable in simple feature-by-feature terms.

How will Turnitin be future-proofing for advanced versions of GPT and other large language models yet to emerge?

We recognize that LLMs are rapidly expanding and evolving, and we are continuously updating our model to detect these additional LLMs. Our focus initially was on building and releasing an AI writing detector for GPT-3 and GPT-3.5, and other writing tools based on these models, such as ChatGPT.  Since then, we’ve expanded our detection capabilities to include a large number of other LLMs as mentioned in the FAQ earlier. Additionally, we have also released capabilities to detect likely AI-generated content that may have been modified by bypassers and paraphrasers.

Can Turnitin detect if text generated by an AI writing tool (ChatGPT, etc.) is further modified using a paraphraser or bypaser tool? Will it flag the content as AI-generated even in this instance?

Yes, Turnitin’s AI detection capabilities include detection of likely AI-generated content that may have been modified using a word spinner/AI paraphrasing or bypassing tool to evade detection. This technology is run automatically for all submissions made to Turnitin by institutions that have the AI writing indicator enabled for their accounts.

Our AI paraphraser & bypasser detection is currently only available for English language submissions.

How will the paraphrasing/bypassing functionality surface in the product? Will it change my workflow?

AI paraphrasing & bypassing detection is integrated within our AI writing indicator. This means that submissions will automatically be checked for AI writing, AI bypassing, and AI paraphrasing, if institutions have AI writing detection licensed and enabled. 

Users will experience no change in their current workflow. Likely AI-generated content that may have also been AI-paraphrased or bypassed will be highlighted and shown as part of the overall AI-generated content in the report.

Which AI paraphrasing & bypassing tools can Turnitin detect?

Our AI writing detector has been trained and tested to detect leading paraphraser and bypasser tools. However, to safeguard the integrity of our solution and its effectiveness in maintaining academic honesty, we’re unable to disclose the names of these tools. Sharing a list of tools that are detected would make it easier for students to evade our system, undermining our collective effort to ensure academic integrity.

Our product teams are constantly working to expand our detection capabilities. We focus on staying ahead of emerging technologies and will continue to update our system to meet the evolving challenges posed by AI tools. Our goal is to provide the educational community with a robust and reliable solution for upholding academic integrity.

Will the AI percentage change over time as the detector and the models it is detecting evolve?

As we iterate and develop our model further to better detect newer LLMs, it is likely that our detection capabilities will also change, affecting the AI percentage.. However, for a submitted document, the AI percentage will change only if it's re-submitted again to be processed.

If students use Grammarly for grammar checks, does Turnitin detect it and flag it as AI?

No. Our detector is not tuned to target Grammarly-generated spelling, grammar, and punctuation modifications to content but rather, other AI content written by LLMs such as GPT-3.5. Based on tests we conducted on human-written documents with no AI-generated content in them, in most cases, changes made by Grammarly (free & premium) and/or other grammar-checking tools were not flagged as AI-written by our detector. Please note that this excludes content generated by Grammarly’s generative AI-powered features, including draft generation, paraphrasing, summarizing, and other features. Content produced using these features will likely be flagged as AI-generated by our detector.

Access & licensing

How can customers get access to AI writing detection?

AI writing detection is only be available to customers that license Turnitin Originality. If you are a Turnitin Similarity, Turnitin Feedback Studio (TFS) or Originality Check customer, please speak to your Turnitin account manager regarding access to AI writing detection.

Please note that for customers licensing TFS, the ‘OriginalityCheck’ listed within the products available when accessing your institutional account dashboard, refers to the component of your institution’s TFS license that allows for papers to be checked against our database, and generate Similarity Reports, and is distinct from Turnitin Originality.

iThenticate 2.0 customers can get access to this feature if they license AI writing capabilities as an add-on. Please speak to your account manager for details.

Is Turnitin’s AI writing detection a standalone solution or is it part of another product?

Turnitin’s AI writing detection capabilities are a separate feature of the Similarity Report and are available to customers when licensing Turnitin Originality in addition to their existing product, or the AI writing add-on, when using iThenticate 2.0.

I had AI writing detection enabled in my TFS sub-account but I don’t seem to have access to it anymore. Why is that?

Since AI writing detection is only available to customers that license Turnitin Originality, we have updated our user-settings in the back-end to manage usage within our products. This means that if your institution decides not to license Turnitin Originality, any sub-account under the main account will lose access to the feature. If you’re unsure about your institution’s licensing or are unable to access AI writing detection despite licensing Turnitin Originality, please speak to your institution’s Turnitin administrator.

Why is AI detection not being added to Gradescope?

We focused our resources on, what we view, as the biggest, most acute problem and that is higher education and K12 long-form writing. We do not currently have plans to add these capabilities to Gradescope, since the primary use case for Gradescope is handwritten text while for AI detection we’re focusing on typed text. However, we are happy to learn more about customer needs for AI writing detection within this product. In addition, we are not pursuing ChatGPT code detection at this time.

Where can I find more information about this new solution?

You can find information in our Turnitin’s AI writing detection capabilities article.

Will Turnitin process my submission for AI writing detection if my institution does not use the feature?

No, we will only process submissions for AI writing detection if the institution has the feature enabled.

Can my institution opt out if we do not want Turnitin to process our submissions for AI writing detection?

Yes, if your institution does not want submissions to be processed for AI writing detection, they can opt out by disabling AI writing detection from their admin account settings page.

If I re-enable AI writing detection, will it automatically show me scores for submissions made before it was enabled?

No, we cannot retroactively process submissions. If you would like to process past submissions for AI writing, you will need to re-submit the document.

Can I request deletion of my institution’s data prior to disabling the feature?

Yes, customers can request a full deletion of their submissions; we cannot support partial data deletion requests to delete only the AI writing component of the submission data.