AI Essay Checker: What Actually Works for Verifying Student Writing

According to the College Board's most recent research, 74% of faculty at colleges and universities report that students are using AI to write their essays.

That's not even a measurement of how many students are using AI and aren't getting caught, either. It only represents the faculty that have noticed.

With this much AI use in academia, learning to recognize the hallmarks of large language models (LLMs) and verify the integrity of student writing is no longer optional. This has given rise to the AI essay checker, which is (for better or worse), yet another LLM that promises to help identify AI use, often with mixed results.

Today, we'll look at what an AI essay checker is, how it works, and whether you can use it to successfully verify student writing.

What Is an AI Essay Checker?

An AI essay checker is a software tool that scans a piece of writing, in this case a student essay, for signs of AI use. The goal is to confirm that the student wrote the essay without LLM assistance, and, in some cases, to check for common spelling and grammatical errors.

The term essay checker covers two different jobs, and it helps to separate them before you evaluate any tool.

Essay Checkers for Grammar and Clarity

The first kind of essay checker helps a writer improve a draft by checking grammar, clarity, structure, and citations. These tools are largely uncontroversial in the classroom.

Common writing improvement checkers include:

• ProWritingAid
• Quillbot
• Paperpal
• Hemingway Editor
• Grammarly (though now bundles AI detection into its suite)

Essay Checkers for Verifying Text Origin

The second kind of essay checker verifies the origin of a text. This includes looking for AI-generated text (i.e., whether someone created the text with a machine), and, sometimes, also looking for plagiarism.

Common examples of this type of tool include:

• Pangram
• Originality.ai
• GPTZero
• Turnitin

Most educators don't take issue with automated grammar and spelling assistance, so those essay checkers aren't the problem when it comes to academic integrity issues.

When you're talking about students using AI to generate their whole essay, however, that's a different ball game. And that's when many educators start seeking out the second kind of essay checker to help them verify the authenticity of student work.

Tip: Some purported AI essay checkers also include AI humanizers, which makes it easy for someone using AI to randomize the text to sound more human (while still being the inherent work of an LLM). This function is the opposite of what you're looking for as an educator, so avoid tools that offer this feature.

What's the Difference Between an Essay Checker vs. a Plagiarism Checker?

We see this particular question often, and it's easy to get the two confused. However, the difference between an AI essay checker and a plagiarism checker is pretty simple: They're solving two different problems.

An AI essay checker asks "Was this written by an AI?" and gives the analyst a score indicating how likely it is that the answer to that question is "Yes." It doesn't tell you where any AI text came from, just that it was generated by an LLM.

On the other hand, a plagiarism checker asks "Was this copied from an existing source?" and looks for near-word-for-word matches across millions of articles, websites, forums, and databases, and provides the analyst with highlights showing its work.

If you're a teacher, you can probably already identify the need for both of these. While there's some overlap between the two (AI can plagiarize based on its training data), each serves a distinct need. There are two ways here in which a student can attempt to work around an assignment rather than complete it, and two different solutions.

How Accurate Are AI Essay Checkers?

Accuracy in the world of AI detection isn't a single number, and no tool is right 100% of the time. Whether any AI detection tool "works" or not is determined by two factors:

• Catch rate refers to whether the detection tool can detect AI use in the first place.
• False positive rate (FPR) refers to the rate at which the tool incorrectly flags human-created writing as AI-generated.

An infographic comparing Catch Rate and False Positive Rate in AI essay checkers.

False positives are a major concern for educators, since presenting any claim of academic dishonesty can be risky, and doing so on the basis of a false positive can end in a wrongful failing grade or even expulsion.

Most detectors have a point of failure. Short text and heavily edited text are the hardest to analyze for all AI detection solutions, but especially with a perplexity-based analysis tool.

That's why Pangram's third-party verified FPR of 0.01% makes it a reliable detector for use in higher education. The neural network detection technology we use holds up against paraphrasers and humanizers, so you can rest assured that the chance of a false positive is as low as possible.

Is Using AI to Write an Essay a Form of Academic Dishonesty?

Writing an essay using AI isn't exactly the same as plagiarism, but most universities treat it as a related integrity violation. The reason boils down to how academic-integrity policies define offenses.

“Plagiarism is the act of presenting ideas, research, or writing that is not your own as your own. Examples of plagiarism include: Copying another person’s or an AI tool’s actual words or images without the use of quotation marks and citations attributing the words to their source."

- City University of New York


According to many definitions of plagiarism, including those by the University of Michigan and Oxford University, the bottom line is that it involves submitting work that you didn't do.

Using an LLM to generate text means you're using the AI's ability to predict likely word sequences to complete an assignment, which is notably different from completing the assignment yourself. When a student submits this work, they're presenting someone else's work as their own, which aligns with the common definition of plagiarism.

How to Check an Essay for AI (Step by Step)

Now that we've established what an AI essay checker is and how it works, let's talk about how to review an essay with a process that can stand up against an audit.

An image showing four steps to check an essay for AI.

1. Run the Text

Your first step is, naturally, to run the essay in an AI detector. You can do this with a quick copy-paste or run it where the work already lives inside your LMS.

Pangram offers a Chrome extension and Canvas/Blackboard integrations, so you don't have to export student writing for grading. If you prefer that workflow, though, have at it!

2. Review the AI Likelihood Score

Once you've run the text, you'll get a score. The score won't be a "yes" or "no," but a scale or percentage of how likely the text was to have been generated by an LLM. This is more of a triage signal for you, rather than a verdict of any sort.

If the essay scores cleanly 100% human-written, you can move on. But a lower score is a signal to examine further.

3. Read the Segment-level flags

For essays that came back with some percentage of AI detected, this is the point where you examine further. This is also the point where a rigorous detector separates itself from the rest.

At this point in the process, Pangram (for example) can highlight the specific passages within an essay that contain AI patterns. You can see where the flag occurs, what caused it, and whether it's three sentences that caused the issue or the entire essay that's under suspicion.

This granularity will come in handy if you have to explain your reasoning to a student or an academic-integrity board.

4. Corroborate With Context Before Any Decision

Finally, you'll always want to compare any flagged passages or even entire works against the student's prior work and voice.

Does the work you're analyzing match past pieces? Does it sound different from the way they write on tests or on paper? The answers to these questions will help you form your judgment.

Throughout this conversation, remember that an AI detector's score is only one piece of a larger puzzle.

What to Look for in an AI Essay Checker

The number one priority when looking for an AI essay checker for anyone should be accuracy. It doesn't do anyone any good to flag human-created work incorrectly, and it can do a lot of harm.

How can we avoid this?

Look for these six things when you're evaluating potential AI essay checkers:

1. A low false-positive rate: Pangram's third-party-verified FPR of 0.01% means that when the tool flags an essay, you can act on it without second-guessing whether you're about to accuse an honest student.
2. Segment-level analysis: A single score for an entire document isn't super useful. Sentence-level flags show you exactly which passages read as AI-generated, so you can see the differences.
3. Simultaneous AI and plagiarism detection: A tool that checks for generated text and copied text in the same pass closes both gaps at once, instead of forcing you to run two separate reviews on every submission.
4. Support for 20+ languages: Unfortunately, some of the weaker detectors may incorrectly flag ESL students' writing as AI-generated. You want to look for broad language support, so your multilingual students get evaluated fairly.
5. LMS integration: A detector that requires you to leave your gradebook just creates more work and more steps. You want to look for an AI detector that makes your life easier, not harder.
6. Independent third-party validation: Most importantly, you need your tool to hold up under scrutiny, so look for a tool that has been tested and verified by independent sources.

If you can find a checker that passes these six checks, you'll know you're evaluating a quality tool that can back up its claims.

FAQ About AI Essay Checkers

Still have questions about AI use in essays and how you can spot it? We've got answers.

Is there a free AI essay checker?

Technically, yes, several tools offer a free AI essay checker, but that usually means limits on word count, on the number of checks per month, or on the depth of analysis you get back.

That sounds fine in theory, but those limits often come with a higher false-positive rate, which makes the scores less useful for academic integrity work.

Do essay checkers really work?

An essay checker typically works well when it has a high catch rate paired with a near-zero false-positive rate. If the checker you're evaluating doesn't publish its detection methodology, be suspicious. Tools that flag a meaningful share of human writing as AI (or vice versa) don't work in any way that helps you.

Can I find a free AI essay checker I can trust for grading?

You can certainly find a free AI essay checker (there are dozens available in a single Google search), but that doesn't mean it will work the way that you want it to. Before trusting any tool, free or otherwise, always make sure a reputable third party has independently tested and verified it.

Find the Right Essay Checker for Academic Integrity

In the end, if you need to verify student writing, you need to know that any tool you utilize to this end will produce results you can trust. That's why we're so proud of our 0.01% false-positive rate at Pangram: It gives educators and academic leaders the confidence to take defensible action.

Want to test it out on your student submissions? Get started with the Pangram Chrome extension and check essays inside your LMS today.