AI Essay Checker — Free AI Detector for Essays
Detect AI-generated essays, research papers, and student assignments in seconds, free with no login. Suspect ChatGPT specifically? Check if ChatGPT wrote it.
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Why Essay AI Detection Matters
AI-generated academic content is growing at pace with AI tool adoption. Detection is now a necessary part of modern academic workflows.
Academic Integrity
Institutions rely on authentic student work to fairly assess learning outcomes. AI-generated essays undermine that foundation.
Fair Assessment
Students who complete their own work deserve to be evaluated on equal terms. AI detection helps level the playing field.
ChatGPT Proliferation
AI writing tools are increasingly accessible. Educators need reliable detection tools to keep pace with rapidly evolving AI models.
How It Works
From paste to report in under 30 seconds — here's the full process.
Paste essay or upload file
Paste essay text directly or upload a PDF / DOCX file.
AI analyzes patterns
Our models evaluate perplexity, burstiness, vocabulary distribution, and structural signals.
Get sentence-level breakdown
Review highlighted sentences flagged as potentially AI-generated with confidence scores.
Review and discuss
Use the flagged passages as a starting point for a conversation with the student, not as a verdict.
Built for Academic Accuracy
Six features designed specifically for detecting AI in essay-format academic writing.
Multi-model detection
Detects ChatGPT, GPT-4, Gemini, Claude, Llama, and more.
Sentence highlighting
Pinpoint the exact sentences most likely to be AI-generated.
Confidence scores
Percentage-based scores with transparent confidence ranges — no black-box verdicts.
PDF & DOCX support
Upload formatted academic documents without copy-paste limitations.
AI providers named
No account needed for your first scans. Essays are sent to the AI model providers listed in our privacy policy only to run the analysis.
No essay text kept
Your essay text is not saved by ProofAI; we keep a record of each check (date, type and score), which signed-in users see in their history.
How to check an essay for AI
Paste the essay above
Copy at least 50 words (ideally the whole essay) into the checker at the top of this page. For Word or PDF files use the document detector or PDF AI checker.
Read the AI score
You get an AI probability and a human probability for the essay as a whole.
See which paragraphs are flagged
Open the full AI text detector for sentence-level highlights: red reads most like AI, green reads like human writing.
Compare and discuss
Compare with the student’s earlier essays and drafts, and ask them to explain their argument before drawing any conclusion.
What teachers notice in AI-written essays
None of these prove AI use on their own, but together with a detector score they help decide which essays to look at more closely.
Generic structure
A neat five-paragraph shape with a predictable “In conclusion” ending and no clear personal argument.
Vague or invented sources
References that do not exist, page numbers that do not match, or quotes nobody actually said.
No link to the class
Nothing about the readings, discussions or examples used in your course.
Sudden change in voice
Writing that is very different from the student’s previous work or in-class writing.
Smooth but shallow
Polished sentences that summarise well but avoid taking a position or going into depth.
Uniform rhythm
Sentences of similar length and structure throughout, which detectors pick up as low “burstiness”.
For students: check your essay before you submit
Running your own essay through an AI checker before submitting is a sensible precaution, especially if you used grammar tools, translation or paraphrasing apps that can make writing look more machine-like. If a paragraph is flagged, rewrite it in your own voice, add your own examples and reasoning, and keep your drafts and notes: version history is the best evidence of your own work.
Remember that detectors can be wrong. Writing by non-native English speakers and very formulaic writing are flagged more often. If you are wrongly suspected, your drafts, notes and ability to explain your argument are your strongest evidence.
AI essay checker vs plagiarism checker
They answer different questions, and many institutions use both.
| AI essay checker | Plagiarism checker | |
|---|---|---|
| Question it answers | Was this text likely written by AI? | Was this text copied from an existing source? |
| How it works | Analyses writing patterns such as predictability and variation | Compares the text against a database of web pages, papers and submissions |
| Catches | Original text generated by ChatGPT, Gemini, Claude and similar tools | Copied or lightly reworded passages from known sources |
| Misses | Heavily edited AI text; can misjudge short or formulaic writing | AI-generated text, because it is new and not in any database |
| Output | AI vs human probability with flagged passages | Similarity percentage with matched sources |
Because AI-generated essays are new text, they usually pass plagiarism checks. That is why an AI checker is needed as well.
Which essays are hardest to check?
Some essays give less reliable results whichever detector you use. Very short answers (under a few hundred words) have little signal. Highly structured writing, such as lab reports, literature-review templates and five-paragraph essays taught as a formula, can look machine-like even when a student wrote every word. Essays that were drafted by AI and then rewritten heavily by the student, or the other way round, often produce mixed scores.
In these cases look at the process rather than the product: ask for outlines and drafts, check the document’s version history, or ask the student to explain a paragraph in their own words. A short conversation usually settles the question faster and more fairly than any score.
Is a 20% AI score bad? What essay scores mean
An AI score is a probability, not a percentage of the essay that was written by AI. A score of 20% means the checker found the writing only somewhat similar to AI patterns; most teachers would not treat that as a concern on its own. Scores in the middle are common for human essays that are polished, formulaic or edited with grammar tools.
A consistently high score across the whole essay, with many red sentences in the detailed view, is a stronger signal, but still a reason to talk to the student rather than proof. Agree on how your department reads scores before you start, so every student is treated the same way.
Frequently Asked Questions
Yes. ProofAI is specifically effective at detecting AI-generated essays, research papers, and academic writing produced by ChatGPT, Gemini, Claude, and other large language models.
Yes. You can detect AI content in essays for free without creating an account. Free-tier detection is available directly from our Detection Hub.
Paste the essay text or upload a PDF/DOCX file into ProofAI's detection tool. Our system analyzes linguistic patterns and returns a confidence score with sentence-level breakdown.
AI detection is probabilistic. A high AI score indicates patterns commonly found in AI-generated writing, but human evaluation should always be part of the process. Our tool provides confidence ranges, not absolute verdicts.
Detect AI Essays with Confidence
Start checking academic writing for AI-generated content — free, instant, and no login required.