5 Best AI Essay Checker Tools

What to know

  • With students using generative AI tools for homework, it has become challenging for educators to discern between human-generated and AI-generated essays.
  • AI essay checker tools have been developed to address this issue, and this article presents the top 5 options, namely GPTZero, Turnitin, Winston AI, Content Scale, and OpenAI’s Text Classifier.
  • When selecting an AI essay checker tool, one should consider its reliability, cost-effectiveness, free features, sentence flagging, and other useful features.

Generative AI tools like ChatGPT and Bing have put the academic world in a pickle. Where it has simplified the task of writing essays for students, the task of teachers is made all the more complicated as they try to find out who’s using these tools and who’s not. 

Fortunately for teachers, if AI can automate essay writing, then it can also automate AI detection. But which AI essay checker tools can you rely on? In this guide, we take a look at the top 5 AI detection tools that will let you identify if an essay is written by a human or AI. 

What are AI Essay Checker Tools?

While the discussion rages over whether using generative AI tools like ChatGPT is really plagiarism, teachers and students as well have begun using AI essay checker tools to ensure that they’re all playing their responsible parts in their education and not looking to cheat. 

AI essay checkers are basically plagiarism checkers that can detect if the sentences in an essay are generated by AI tools like ChatGPT. Depending on how they’re modeled and trained, they can either be decently reliable or ridiculed with false positives that will flag even human-generated content as AI. AI essay checker tools are not always going to work, and they may not always be 100%. Playing catch-up with these AI technologies is not easy and will inevitably lead to half-baked AI detection tools. 

But that is not to say that there aren’t a few that have managed to crack the code and developed models that work well enough to catch AI-generated content while giving human-written content a pass. Below we highlight the top 5 AI essay checker tools that belong to this category.

5 Best AI Essay Checker Tools

Here is what we think are the best AI essay checker tools going around right now.  

1. GPTZero

GPTZero is a Reddit favorite, not least because it is free to use for everyone, not just the professors. And it’s fairly easy to use too. Just visit GPTZero, paste the content (or upload a DOC, PDF, or TXT file), and click on ‘Get Results’ to know if the content is written by a human or an AI. 

Besides checking for AI-generated content, GPTZero will also provide additional stats about the essay, such as the level of randomness and perplexity in the text. Low scores in these categories are clear red flags that the writing is generated by AI.

Like many other AI detectors, its accuracy can be off depending on the level of analysis. So, a complete document-level analysis is better than a paragraph-level, which is better than a sentence-level analysis. Unlike Turnitin, GPTZero “is not trained to identify AI-generated text after it has been heavily modified after generation…” So that’s something useful to know, for both the teachers and the students using it. There is a paid subscription plan for teachers as well, but the free version has much that many users will think is enough. 


  • Free to use
  • Ability to upload document files
  • Provides stats for ingenuity and complexity.
  • Will highlight AI-generated content in yellow.


  • Checks up to only 5000 characters in the free version
  • Batch file upload limited to 3
  • Can have problems with edited AI-generated text.

Related: Is GPTZero Accurate? Can It Detect ChatGPT? Here’s What Our Tests Revealed

2. Turnitin

Turnitin is easily one of the best of the lot. It doesn’t claim to deliver 100% accuracy for everything that you upload for checking. But whatever it does flag as AI-generated, it gets it right 99% of the time. In a YouTube demonstration, Turnitin’s AI detection abilities were put on display and the tool is seen to work even in cases where the sentences have gone through minor changes and edits, as students are wont to do before submissions.

Turnitin’s AI-detection model focuses largely on higher education writing where it works really well. Though it also can be used for middle and high school writing, the chances of generating false positives there are higher. 

However, these details don’t diminish the fact that Turnitin is an AI essay checker par excellence, and easily one of the best ones that educators and professors should try out.


  • High precision and reliability, especially for higher education writing.
  • Detects even when changes have been made to AI content.


  • Only for educators and teachers to use.
  • Paid service only

Related: Can Professors Detect Google Bard and ChatGPT?

3. Winston AI

Winston AI Detection is one of the few commendable AI detectors to have emerged in the wake of the generative AI tsunami. It has multimodal support for AI detection, allowing you to upload complete documents and image files for analysis. If you get a paid plan, you will also have access to the OCR feature, allowing you to snap a picture of hand-written essays and letting Winston extract words from them for analysis. This is a super feature that can greatly simplify the work of not just those in academia but also in other fields like content creation and web publishing. 

Winston’s document scoring is impressive too, ranging from ‘AI-generated’ to ‘Human’ in scale. The visual grading tells at a glance how likely it is that a piece of text is written by AI.

Though the free features are limited to AI detection, paid plans will let you catch plagiarism, generate a list of duplicates found in the text, and also create a printable report to keep in your records. After the 7-day free trial ends, you will inevitably have to get a subscription if you want to continue using Winston. But given its long list of features, it is one of the better AI detectors out there that is worth the price tag.


  • OCR for hand-written essays
  • Support for image and document formats
  • Visual grading system 


  • Free use for only 7 days
  • Subscriptions are on the expensive side 

4. Content Scale

The number of AI detector tools out in the market today is growing by the day, but some names, like Content Scale, continue to crop up again and again in the discussion. Like many of its ilk, it too uses a mix of AI engines, analysis algorithms, and language models to determine if a piece of text is (potentially) AI-generated or human.

Though it won’t be able to detect the higher sophistication of GPT-4 language modeling, Content Scale is one of the fewer AI detectors that you can expect to provide all the useful features that anyone starting out will need. Add in the fact that it is free to use, can flag AI-generated sentences, and has a grading wheel that scores for ‘predictability, probability, and pattern’, and you have yourself another winner.


  • Supports up to 25,000 characters
  • Free to use
  • Highlights AI-generated sentences


  • No GPT-4 support

5. OpenAI’s Text Classifier

OpenAI, the company behind the revolutionary ChatGPT, has its very own AI essay checker tool. But even with their seminal GPT technology and tons of data to work with, this text classifier is not always accurate which goes to show how difficult the process actually is. 

Nevertheless, as a free AI detection service, it gets the job done for the most part. Using it is a cinch as well. Simply enter the text in the ‘Text’ field and click on ‘Submit’. The results won’t highlight which sections or sentences were written by AI. Instead, you will get a statement telling you if the classifier considers the text to be either “unlikely, likely, unclear if it is, possibly, or likely AI-generated”.

OpenAI openly states that the effectiveness of the classifier hasn’t been thoroughly assessed. This may not inspire a lot of confidence in the AI essay checker. But if you are suspicious of the contents of an essay and simply want a second opinion, this AI text detector can prove useful too.


  • Free to use
  • Simple UI (works with your ChatGPT account)


  • Not as reliable as other tools
  • Doesn’t highlight possible AI content.
  • Effectiveness not assessed by OpenAI

Things to look out for in an AI essay checker tool

There is no shortage of AI detectors or essay checker tools nowadays. Most of them will offer their services for free, with a subscription fee that unlocks additional features. But when you’re out exploring you should consider looking out for the following things to get the tool that fits your needs:

  • Reliability – The reliability of an AI detector can either make or break the deal. If what the tool detects is unfairly biased and fraught with false positives, then you should definitely look the other way. The easiest way to find this is to try it out yourself. Feed the detector AI written material and check the results. Then feed it content that you know to be human-generated and see the results. If the detector gets it right more often than not, it’s a keeper. Some tools, like Turnitin, will outright tell you what they can or can’t do, which is a big plus since you know what you’re getting with them.  
  • Free features – Most free AI essay checkers have some restrictions. Some will have severe character limitations while others will allow long essays to be analyzed on the go. They may also have result-based restrictions, in that you may or may not see which portion of the essay was AI-generated. Some others will allow multimodal essay support for document and image formats. All this will vary depending on the AI checker you’re using. So do go through the AI detector’s website to see what’s available.  
  • Costs and Value – Not all AI essay checkers are free. In fact, some of the best ones only let you use the services for a short trial period concluding which you will have to pay for a subscription. But they may not always be for you. A paid subscription for AI detectors is only viable if you have tons of essays to check or if the available features are too good to let go.
  • Sentence flagging – This is another important feature that you should check. Many free AI detectors, like OpenAI’s Text Classifier, won’t highlight which sentences it thinks are AI-generated. But there are many more that do, and fairly accurately too. Getting down to the paragraph and sentence level of analysis is not easy, but because it provides valuable information that can help tell where the text has been copied from AI generative tools, it is worth keeping in mind.    
  • Other features – Visual scores and results, printable reports, and parameters for analysis are a few examples of additional features that add to an AI essay checker’s advantage. You may choose one AI detector over another based on how useful these features prove to you and simplify your work.  

AI detection technology is still in its nascent stage, but many companies are actively developing their own AI detection models to stand out in terms of accuracy, reliability, and features, and take the technology further. It helps to get other users’ perspectives as well. So make sure you also check out what fellow users are saying on forums like Reddit and Twitter, especially if you plan to purchase a subscription.  

Related: Midjourney Cheat Sheet: Become a Pro at Using Midjourney!


Let’s take a look at a few commonly asked queries about AI essay checker tools.

Are AI essay checkers reliable?

AI essay checkers are reliable, but not a hundred percent. The fact that AI detector models are still being worked and improved upon, and fighting to catch up with the latest AI capabilities makes AI essay detection with complete accuracy a hard nut to crack. However, there are many AI essay checkers at the frontiers working to improve their tools and models, such as the ones mentioned in our guide above.

Can teachers detect AI writing?

Depending on how well your teachers know you and/or which tools they use to detect AI generated content, it may be possible for them to detect AI writing fairly easily. Know what your institution permits and make sure to follow the guidelines if you don’t want your essay flagged. 

Is ChatGPT plagiarism?

The discussion involving ChatGPT and plagiarism is ongoing. Its proponents (read students) call ChatGPT and other generative AI tools just another means to get information, while many educators and professors consider even its instrumental use as plagiarism. Head on over to our guide on ‘Is ChatGPT Plagiarism?’ where we discuss the issue at length and talk about how teachers should look to adopt this powerful technology rather than shun its use going forward.



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