Although AI tools provide various benefits in both the education and business sectors, there are also unethical use cases. One of these cases is writing an entire essay or content by AI. AI-generated content has repetitive phrases and ideas but is difficult to detect. However, you can detect AI-generated content by using AI plagiarism checkers. 

In this article, we will examine how AI plagiarism checkers work and the best of them.


  • With the popularity of AI writing tools, we frequently encounter AI-generated essays and blogs.
  • You can use AI plagiarism checkers or AI content detectors to check whether the content is AI-generated.
  • These tools provide a result by analysing the content's writing style, repetitive phrases and ideas, grammar, and syntax usage with trained data.
  • The best AI plagiarism checkers that will allow you to detect AI-generated content are TextCortex Plagiarism Checker, GPTZero, Copyleaks and Grammarly.

How AI Plagiarism Checkers Detect AI-Generated Content?

AI plagiarism checkers and AI content detectors use Large Language Models when analysing whether the content is AI-generated. Simply, an AI content detector asks itself “Is this content that I would have written?” to analyse the given content. If the answer is yes, the content is assumed to be AI-generated. There are also a few different methods that AI plagiarism checkers use to determine whether the content is AI-generated.

Writing Style

One of the methods used by an AI content detection tool is to check the writing style. Large language models generally generate output in specific patterns. AI plagiarism checkers scan whether the given content is AI-generated based on those patterns.

Repetitive Phrases

AI writing tools tend to use repetitive phrases and ideas to generate content while adhering to the given keywords. If you use the same phrases and ideas frequently in a single paragraph, your content can be tagged as AI-generated.

Unusual Syntax 

Have you noticed that the grammar, syntax, and tone of voice of content you have read before suddenly change? Hasty changes in grammar, tone of voice, and syntax in content usually indicate that the content is AI-generated. Especially, sharp changes in the middle of a paragraph tagged by AI plagiarism tools as AI-generated content.

Trained Data

When AI content detectors analyse a paragraph, they rely on trained data from large language models. So, they can identify differences between human and AI-generated content. If the trained data of an AI content detector is limited, the accuracy of the tool will decrease and cause false reports.

If you want to make sure whether the content is AI-generated or human-created, you need to use a tool trained with a large amount of data.

Best AI Plagiarism Checkers to Detect AI-Generated Content

If you want to accurately detect the plagiarism score of content, you need to use a high-quality AI tool instead of one with limited training data. Fortunately, AI plagiarism checkers with large amounts of training data and real-time web search features will do the trick. Let's take a closer look at the best AI plagiarism checkers to detect AI-generated content.

TextCortex Plagiarism Checker

TextCortex is an AI-powered assistant that offers various writing features including Plagiarism Checker. You can use all its features in 25+ languages to complete your writing tasks quickly and gain extra free time. TextCortex is available as a web application and browser extension. Its browser extension is integrated with 20.000+ websites and apps, so TextCortex can accompany you throughout your internet adventure.

AI Plagiarism checker

When it comes to AI-generated content, our Plagiarism Checker can detect it with high accuracy with its trained data and large language models. To use our plagiarism checker, you need to follow these steps:

  • Create your free TextCortex account
  • Head to our web application
  • Click “AI Editor” from the drop-down menu on the left
  • Copy-paste, write or upload content
  • Click on “Plagiarism Checker” at the bottom right of the screen.
  • Click “Scan for Plagiarism” in the Middle-right part of the screen

and that's really all. Our plagiarism checker will analyse up-to-date internet data and LLMs to create a report on your entire content. In this report, you can check which sentences were plagiarized from which websites or articles, and the overall plagiarism score of your content.

If your content has a high plagiarism score, you can reduce it by using correct citations. Especially in academic articles, any information you use must come from scholar and reliable sources and be properly cited. Before the development of AI, finding and citing reliable sources for your academic essay topic was a headache. However, by using today's AI technologies, you can access academic resources related to your topic with a single prompt.

Find Primary Academic Sources with ZenoChat

ZenoChat is a conversational AI with functions such as text generation, question & answering, translation, paraphrasing, and tone changing. Moreover, ZenoChat comes with a web search feature where you can search only targeting Scholar resources. Using the ZenoChat web search feature, you can quickly find peer-reviewed papers and reliable research related to your essay topic.

ZenoChat will provide a brief summary of these resources in addition to their URL. This way, you can easily find which source has the highest compatibility with your topic and avoid wasting time!


Grammarly is a reliable and useful tool for both essay writing and plagiarism checking. Using Grammarly, you can fix spelling & grammar and punctuation errors in your content. Additionally, Grammarly will analyse your content and highlight passive voice usage, hard-to-read sentences, wordy sentences, incorrect phrasings, and complex sentences.

AI content detector

Another impressive feature of Grammarly is its plagiarism checker. Grammarly's plagiarism checker tool is one of the most frequently used and gives the most accurate results. To use the Grammarly plagiarism checker, you can manually write your content or upload your document. Although Grammarly shows the plagiarism score of your content for free, you need to purchase its premium subscription to see plagiarized sentences.


GPTZero is essentially a tool designed to detect content generated by ChatGPT. GPTZero is useful not only for detecting AI-generated content but also for checking plagiarism. It uses statistical data to understand if the given text is written by a human or AI.

gpt zero

Since GPTZero is trained with text generation algorithms and data from popular large language models such as ChatGPT, GPT-4, and Bard, it can detect AI-generated content with high accuracy. However, it does not always provide 100% accurate results, so we recommend double-checking the results.

Copyleaks AI Content Detector

Copyleaks offers two different AI-powered tools for both plagiarism checking and AI content detection. To use Copyleaks AI content detector, all you need to do is enter your content into the textbox and click the "Check" button. Afterwards, Copyleaks will analyse the given text and highlight the AI-generated parts with red.

AI Content detector

Copyleaks plagiarism checker analyses the given content by scanning one of the internet or internal database options in 25+ languages. Copyleaks plagiarism checker also has an option that checks whether the content is AI-generated or not.

ai plagiarism checker

Overall, all of these tools can provide great insights. But keep in mind that it always boils down to utilizing AI to augment your writing and making things easier when it comes to AI