9 Best AI Writing and Plagiarism Checkers for Teachers

Integrity is an important factor in education, and the introduction of AI writing tools haven't helped… at all. 

AI tools like ChatGPT pose major threats to the modern education system.

It's becoming easier and easier for students to use AI writing tools to pass off fully AI-generated work as their own. We've entered a gray zone where teachers are facing a constant battle to detect and prevent AI plagiarism.

Along with this recent AI boom came tools that help predict AI writing by finding patterns in a submitted text. With the use of advanced algorithms and natural language processing models, AI plagiarism detection tools are made to quickly identify instances of AI misuse.

The Best AI Writing Detection Tools for Teachers in 2023

Tools like ChatGPT are nothing short of incredible & have resulted in tons of new creations, essays, and business ideas around the world. But with that comes cheating. 

Each of these detection tools work slightly different & carry certain purposes over others. Convenience is also a big issue, especially if you're testing 30 pages of essays each day. With all of this in mind, here are the current best AI text detection tools currently on the market:

1) Winston AI (built for teachers)

If you're looking to bulk test academic/education content, Winston is your go-to. Winston AI self-proclaims to be the best academic AI detection software.

It's similar to Originality, but focused specifically on educators looking to check for students who used AI. You can start for free (their trial is 2000 free words for one week) but need to upgrade if you have a larger quantity of papers to check.

When you submit a document, you'll get a human score (based on the likelihood a student wrote it using AI), a plagiarism score (includes links to the writing it was stolen from, but this isn’t available on the free trial), and a readability score.

These all work together to give you a pretty solid understanding of where this writing came from. If you see university level writing for a middle school english class, something is probably up.

Winston is super easy to use, supports OCR (you can upload written documents and have it scan a specific essay to check for AI), and is extremely fast.

Winston also lets you generate a report in 1-click, very great if you want to show your students insight into why they were flagged as using AI. Pretty awesome, right?

But those aren’t as important as this question: is Winston AI accurate?

The short answer is yes. Their own testing (which shouldn’t be taken at face value because, let’s face it, it’s their own test) produced an accuracy score of 99.98%. Our own test found it to be the most accurate in identifying true positives at a rate of 91.92%.

If you do anything in the educational sector, you need to check out Winston!

2) Copyleaks (free & easy)

I'd say Copyleaks is one of the best out of the box. It's simple, has a free plan, and takes a few seconds to get you a verdict.

A recent research paper from Cornell University found that their AI detector is the best at spotting text made by AI tools like ChatGPT (especially the newest update which includes GPT-4) and Claude. We, on the other hand, found it to be third-most accurate in true positive tests and second in false positives.

They claim to be 99.1% accurate and can tell if the text was written by an AI in more than 15 languages. It shows which parts are likely made by an AI by highlighting them (but this isn't as accurate as the holistic score and it’s not available in the free version).

It claims to find content that was reworded from AI-made text. You can use a basic version for free, but if you pay $10.99 a month, you'll also get a plagiarism-checking feature. Talk about hitting two birds with one stone.

3) Originality

I've been using Originality's AI detection tool since it initially came out to check various types of content (academic papers, business industry reports, and online blog posts).

It's fast, easy, and accurate. Originality claims to be made for serious content publishers over those in academia. But its UI, flexibility, and visualization are way ahead of other tools, especially when checking a ton of submissions at once.

Originality costs 1 cent per hundred words, making it one of the most affordable options to check many papers in a short time. To put this into perspective, to check 30 essays each around 1500 words, will run you about $4.50.

Compared to other tools, Originality also includes a percentage in its prediction score. You'll see something was 2% likely to be AI and only 98% likely to be human-written (these will add up to 100). Here's what it looks like in action:

A great feature about Originality is line-by-line highlighting. You'll see sections marked in orange which indicate it might be written with AI. Green sections show human-writing. The more text you enter, the larger sample size Originality has to work with (increasing the reliability of your result).

As you can see below, a decent amount of the paragraph was highlighted in orange, but as a whole the article is in the clear. (This is true, I tested it with a college academic essay!)

4) Leap.AI's GPT-4o AI Detector

Another tool that's been updated on one of OpenAI's newest models, GPT-4o, is Leap's AI detector.

Leap can scan either an entire section of writing or go line by line to predict if something was written with AI. They also have a built-in writing feedback tool where you can get insights.

While I personally think AI detection is more accurate when scanning complete articles/essays of writing, I think it's interesting to see a breakdown by each line.

Their base plan starts at $14/monthly for a single seat. It comes with 100 Tasks & 10,000 AI Credits which you can use on their content detector and other tools like:

• Image Generator
• Text to Speech
• Paraphraser
• YouTube to Blog

I'd recommend checking out Leap if you want something that cuts straight to the point, is super easy to use, and has a sleek design that doesn't require you to do anything complicated to get what you need out of the tool!

5) Undetectable AI Plagiarism Detector

Along with their paraphraser that can humanize AI text, Undetectable AI has an AI Plagiarism Detector that can help determine if something was written with some of the popular AI text generators (aka ChatGPT and Claude).

Well, not exactly. What Undetectable AI does is better because it averages the AI likelihood score from 8 different detectors (Content At Scale, Sapling, GPTZero, and more) so you can have a better overview of whether a piece of text or document came from an AI. 

Honestly, the only complaint I have about it is the lack of bulk testing features. Other than that, it's fairly good at detecting when someone used any of these tools to write something and will even give you a breakdown of why it flagged something:

6) Passed AI

Passed.AI is a newer AI detection tool that is specifically for teachers. The model is trained on GPT-J, GPT-NEO or GPT-3 to detect AI writing based on patterns. They further claim to be trained on GPT-4 directly from Originality (but they still tailor the rest of their features specifically for educators).

They also have a Chrome Extension for quick-checking documents, which you can even do inside of Google docs. A unique feature about Passed is how they let you "replay" a Google Doc to see edit history. This is great for auditing an entire document based on how it was written

The company claims that AI Detection alone is NOT enforceable. But when combining AI detection with a document history audit will provide an unparalleled confidence in AI detection. All you need is edit access to the Google document the student submitted and Passed.AI can provide you a detailed audit.

• "Replay" at 10x speed
• See the number of contributors and the size of their contributions to the text
• See if the words/minute were natural or not
• No software for students to install

The actual AI detection page is similar to any other software. To use, paste suspected text into the scanning box and start scanning. You'll get a percentage score indicating the likelihood a sample was written with AI. A score of 100% Not AI and 0% AI should be thought of as "We are 100% confident that this content was created by a human."

7) Content at Scale

The next tool we'll talk about is called Content at Scale. If you're looking for an AI detection tool that tends to not over-flag people, this is probably it.

I've tested old academic essays, ChatGPT responses, and random articles I found online and have found the tool holds up very well, but doesn't like to claim something as AI if it's not true.

This detection software is also free, it's just a bit harder to test dozens of articles quickly with it. 

The company behind this actually creates fully written, complex website blogs; so they built a detection tool to see if their writing is able to be detected by AI (it's generally not!). Here's a few examples of an academic research paper, poorly written paper, and ChatGPT answer:

8) GPTZero (Individual Academic Content)

The next resource that could be used in detecting AI writing is GPTZero. This tool was actually created by a student at Princeton in early January. It works by assigning text both a perplexity and burstiness score. Perplexity measures how random the text is while burstiness measures its variation. The higher both of these values are, the more likely the document was human-produced. 

We have a complete review on GPTZero if you want to learn how it works.

The tool also highlights text that might be written with AI (if it's only a few lines in an essay, compared to the entire document). Again, these tools should be used with your own judgment, but it's a good initial starting point if you detect something was written by some AI-writing software (even if it’s rewritten by an AI bypass tool).

You can use GPTZero by uploading a full document (as a pdf, docx, or txt) or pasting text directly into the tool. Once uploaded, you'll see the predicted result in large bolded text.

You can see what text has been predicted as likely AI if you scroll down. This text will be highlighted in yellow and can appear at any point or sentence throughout a submission.

You'll also be provided with the perplexity and burstiness scores of the submission, but these scores don't really tell you anything beyond the scope of their definitions. It's best to use GPTZero based on its final prediction & color flagging.

9) Sapling (Free and Trusted AI Detector)

AI detectors shouldn’t hurt your wallet — something that Sapling understands all too well.

This free tool has everything you want in an AI detector: it’s backed by an accurate model (ranked among the best in our testing) and outputs an AI likelihood score, along with highlights on specific parts of your input that are likely machine-generated. It also supports uploads, so you don’t have to worry about copy-pasting documents.

It’s also regularly updated whenever a new LLM is out on the market so that they can stay ahead of the AI content detection game. And, as per their latest changelog, they’re also going to start supporting code inputs in the future — so we better stay tuned. 

How Does AI Detection Work?

Although not mathematically provable, AI writing detection tools try to re-predict the same text you're trying to test. Because of how AI works, it generally produces fairly consistent text structures. LLMs follow formulaic patterns of what it was trained on, since that's what it knows best. 

Since humans are so versatile and complex, our writing doesn't include as many predictable patterns & sentence structures. The best writers often have an unpredictable vocabulary that engages and questions their audiences in ways AI can’t do.

The more accurate a detection tool can recreate the same sentences you are trying to detect, the higher chance what you're looking at has been written by or at least assisted by AI.

If you want more of an in-depth explanation, check out our more technical explanation.

As such, these tools should be taken with a grain of salt.

In 2022, students have been accused of using AI-generated writing because of TurnItIn's new AI detection software. I'm sure some of them were innocent and just happened to get flagged by these tools. So, you may ask: “What exactly is the false positive rate for AI detection?”

The answer is, we don’t know — and that’s the scary part.

Claiming a single piece of paper was written with AI because of the result of a detector is still not proof that a student used AI. I've written tons of articles that have flagged me as using AI when I didn't use anything at all. These tools can help you predict, not determine.

While I wouldn't fully rely on AI detection tools if you are a teacher, they can be decent indicators when tested on multiple instances of a student’s writing.

The last thing you want to do is accuse a student of using AI just because you tested a single article they wrote. I hate to break it to you, but this can of worms can not be solved this easily. It's probably never going to be solved.

A few years ago, OpenAI claimed that AI detection is unreliable and promptly took down their own detector. Now, in 2024, sources claim that OpenAI has a new detection model that’s 99% accurate, way better than anything we’ve ever seen — but they’re reluctant to release it. The reason?

It’s the 1% that kills you.

Want to avoid this headache? Just have students write and submit things on paper in class. Sounds old school but it's the only headache free method that is actually perfect.

Final Thoughts

All of the tools on this list serve their specific purpose. Before going all in on one specific AI detection tool, you should carefully consider the features and use cases for each tool, as well as features that would best align with your classroom and school standards.

Remember to always be mindful of AI detection. There are many ways to help detect content that include your very own judgment. Keeping all these things in mind, you can always test out various detection tools to see what fits right for your assignments and workload.

Have I missed any of your favorites on this list? Which of these detection tools have you had the best luck with? Let me know in the comments!