AI plagiarism is one of the biggest academic and professional concerns of 2025.
With advanced models like GPT-4 Turbo and Claude 3, it’s harder than ever to tell whether content was written by a human or AI.
You’re not alone—only about one in three people can accurately distinguish AI‑generated text from human writing, according to a 2025 survey highlighting growing concerns over content authenticity.
This gives rise to what researchers call the threat of ‘AI plagiarism’:
A growing number of students and professionals are using AI to generate content that may be subject to plagiarism penalties.
In this article you’ll discover:
How to check for AI plagiarism
Whether or not AI is subject to plagiarism laws
The best AI plagiarism checker tools available in 2024
Let’s dive right in.
Key Takeaways
AI writing is often mistaken for human, even by experts
Schools now penalize undisclosed AI-assisted work
Most plagiarism tools miss AI-generated content
Undetectable AI helps rewrite and avoid detection
AI detectors are essential for ethical content use
What Is Plagiarism?
According to APA Style, ‘plagiarism is the act of presenting the words, ideas, or images of another as one’s own’ — and whether deliberate or not, it violates the ethical standards of scholarship.
In plain English, this means that plagiarism is representing another person’s work as your own.
This extends beyond human authorship: submitting AI-generated text without disclosure can also constitute plagiarism.
Is Plagiarism Illegal?
Plagiarism is not a crime under criminal law. However, it may lead to the following results that may be pursued in court:
Copyright infringements. In short: You make money out of someone else’s original work (where they should make money out of).
Breach of contract. In short: An employer hires you to create original work. Yet you deliver plagiarized work.
According to the Citadel, copyright infringements can lead to jail time in severe cases. However, breach of contract is typically limited to monetary punishment, according to Cornell Law School.
Is Plagiarism A Crime?
The act of plagiarism itself is not a criminal offense.
Plagiarism itself isn’t a crime, but copyright infringement and breach of contract can lead to lawsuits, fines, or even jail time in extreme cases.
Attributing sources appropriately and respecting others’ intellectual property rights is essential. It’s the morally right thing to do, so it’s good karma (as Steve Jobs would say).
Avoiding plagiarism is especially important as a student:
What Are The Consequences Of Plagiarism As A Student?
Typically, plagiarism as a student is not pursued in court but may lead to internal punishment. Such as:
Failing an assignment
Failing a course
Removal from a major
School suspension
All of these situations can bring severe and long-term professional consequences, that may be difficult to recover from as a younger adult.
While most students who use plagiarized content are aware of their behaviors – some may not. It turns out that using AI as a help for essays and papers may also result in plagiarism.
As of 2025, many universities have explicitly banned undisclosed AI use in coursework. Penalties can now include assignment failure, suspension, or expulsion.
“AI creates content by drawing on a large library of information that’s already been created, but is it plagiarizing?”
Large Language Models today, like GPT-4 Turbo and Claude 3, generate text based on massive datasets that include licensed material, public domain sources, and synthetic data.
While their outputs are usually unique, they may still overlap with copyrighted or proprietary content, which is why many turn to AI detection tools to verify originality.
Researchers often describe LLMs as “stochastic parrots”—systems that assemble logical sentences without true understanding.
If these sentences resemble original authored material, or training data that comes from protected sources, the results can border on AI plagiarism, even if unintentionally.
To mitigate this, some writers use tools to humanize AI content before publishing
Does Chat-GPT Plagiarize?
Is using AI plagiarism? It depends on how the text is produced and disclosed.
Modern large language models are trained on a mixture of publicly available and licensed data (plus synthetic data and human feedback), i.e., hundreds of billions of words rather than a fixed “books” count.
The sheer amount of data Large Language Models (LLMs) are trained with means two things:
Because training datasets are vast and diverse, verbatim copying is uncommon—but overlap with copyrighted or proprietary material can still occur.
That’s why disclosure and citation are critical when you use AI to draft content.
If you combine a large amount of original work, you may create content that is so different from the original that it can’t be traced back to it.
This is what researchers found in a recent study called ‘Will ChatGPT Get You Caught?‘. The researchers tested ChatGPT-created essays with plagiarism checkers such as Turnitin and iThenticate.
Result: in that experiment, 40 of 50 essays (80%) showed ≤20% similarity in Turnitin/iThenticate—i.e., they appeared “high-originality” to plagiarism checkers.
However, follow-up research shows paraphrasing attacks can evade many AI detectors, and detection tools can produce false positives/negatives, so no single checker is definitive.
Bottom line: AI-written text can look “original” to traditional plagiarism checkers, but that doesn’t mean it’s undetectable as AI. Use both a plagiarism checker and a modern AI-writing detector—and always disclose and cite sources appropriately.
Can Universities Detect AI Plagiarism?
Similar to the study mentioned above, most universities rely on well-established tools such as Turnitin and iThenticate to detect plagiarism.
This creates gaps in detection, because while tools like Turnitin and iThenticate now include AI-writing detection modules, their accuracy remains inconsistent — producing both false positives and false negatives, especially with newer models like GPT-4 Turbo and Claude 3.
By 2025, many universities have adopted AI-detection add-ons within Turnitin, but enforcement varies widely across institutions.
This doesn’t mean you should rely on AI to get through university. Always remember that the purpose of going to university is to help you understand your topic of study.
University prepares you for a competitive 21st-century workplace. You can only be properly prepared if you internalize your field of study by investing time and energy whilein university.
Using AI may help you make your studying efforts more effective – and write your papers and essays more quickly.
Because detection isn’t foolproof, students and professionals increasingly use tools like Undetectable AI’s AI plagiarism checker to verify their own work before submission.
Make sure you understand what you’re writing about (and conceal any AI-generated content effectively).
Here’s how you can do that:
How To Check For AI Plagiarism? The Rise of AI Detectors
Given that conventional plagiarism-detection software considered the ChatGPT-generated essays as human-written, it’s worth looking at alternatives for educators and AI users alike.
What is required is a first line of defense: A tool that checks whether or not the text was generated by AI (before checking it for plagiarism in the conventional way).
This tool is called an ‘AI detector’.
There are plenty of AI detectors available that can accurately identify AI content. For educational institutionsand students and professionals alike who want to ensure that their content is not flagged by common AI or plagiarism checkers, these have become a must.
One of the best AI detectors is Undetectable AI. It can accurately screen content for signs of AI, has over 5,000,000 users – and has been featured by Forbes.
Did AI Write This? How To Identify AI-Generated Text
Peer-reviewed studies show that humans, regardless of age, are unreliable at spotting AI-written text — most readers misclassify it about 50% of the time
So, it’s not that exposing yourself to text written by AI may help you distinguish it better. It may actually unconsciously help you build a tolerance towards it.
The most effective way to identify AI-generated content is to use specialized detection tools trained on large datasets of both human and AI writing — essentially, it takes one algorithm to catch another.
These systems are known as AI content detectors or simply AI detectors.
They analyze subtle linguistic patterns, token probabilities, and sentence-level anomalies that humans cannot reliably perceive — making them far more accurate than manual judgment.
How To Avoid Plagiarism Using AI
There are a few best practices to avoid plagiarism when using AI-generated text:
Ask LLMs for the primary sources of their information in the prompt (Do not use ‘ChatGPT’ as a source).
Use AI-generated content as a starting point, not the final product.
Rephrase the content you use from LLMs.
Follow the specific guidelines and ethical standards of your field.
Double-check the end result by testing it with an AI detector such as Undetectable AI.
Use Humanize AI (also offered by Undetectable AI) to automatically rephrase the content. This has less AI detection likelihood than manually rephrasing it according to this study.
Traditional tools like Turnitin and iThenticate remain valuable for plagiarism checks, but they struggle with detecting AI-generated content. I
n 2025, the best results come from combining plagiarism checkers with dedicated AI detection tools.
They may be used in combination with one of the following free AI detectors (and AI plagiarism checkers) for the best results:
Undetectable AI — Best Overall (AI detection + humanizing rewrite; trusted by 5M+ users, Forbes-featured)
Copyleaks AI Detector — Best for Academic Institutions (integrates with LMS systems; highly adopted in 2025)
Originality.AI — Best for Publishers & Agencies (team-friendly, bulk scanning, popular in SEO/content teams)
GLTR — Good for detecting older GPT versions (but less accurate for GPT-4 and newer)
ZeroGPT — Lightweight, decent option for freelancers
Sapling — Useful for agencies that need Chrome extension + CRM integrations
Modern detectors use techniques such as linguistic forensics, token probability analysis, and watermark detection to flag AI-generated text patterns.
You can find an in-depth review of the above AI detectors, along with six more AI detectors, here: Top 10 Best AI Content Detectors
Our AI Detector and Humanizer are available in the widget below for your convenience.
Conclusion: Was This Written By AI? AI Plagiarism Checker
AI content is here to stay, and it’s getting more indistinguishable from human-written content by the day.
In controlled experiments, GPT‑4 was judged to be human in a Turing test 54% of the time — indistinguishable from humans and significantly higher than GPT‑3.5.
Earlier claims that older adults were better at spotting AI text don’t hold up anymore — newer studies suggest younger users are catching up quickly, often using sharper digital literacy and detection strategies.
The only viable solution for business owners, institutions, and professionals who want to avoid penalization due to plagiarism or other concerns, is effective AI plagiarism checkers.
While there are many well-established sources, such as Turnitin and iThenticate, we recommend using newer AI detectors in combination with them to give the most effective results.
Especially since a lot of AI detectors are free and easy to use. You can test our AI detector of choice – Undetectable AI.
