Check whether writing shows patterns associated with AI-generated text. PlagPointer analyses documents for AI writing, including text produced or refined with major generative-AI systems, and gives you more than just a bare percentage to review.
- 30 supported languages
- 3 sensitivity levels
- Explainable AI insights
- Pay as you go
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- Plagiarism and AI detection in one scan
- Detailed PDF report saved to your account
- No subscription — credits do not expire
AI detection requires at least 350 words. Source-code files are checked for plagiarism, not AI text.
One job, several names
AI detector, AI checker, AI content detector: what does it actually do?
Whether you call it an AI detector, AI checker, AI content detector, AI text detector or AI writing detector, the aim is the same: to estimate whether a piece of writing contains patterns associated with text generated by a large language model.
PlagPointer is designed to help you investigate that question, not to pretend a probability score is proof of authorship. It can be useful when reviewing essays, articles, reports, applications and other prose, but AI-detection results should always be considered alongside the document itself and the wider context in which it was written.
What you get
More useful than a simple “AI or human” label
Modern AI writing is rarely a neat block of untouched chatbot output. A useful AI checker needs to cope with mixed, edited and model-generated text while making the result easier to interpret.
Three AI sensitivity levels
Choose Extra Safe, Balanced or Extra Sensitive depending on how cautiously you want the detector to behave.
Major AI model families
Check writing associated with systems including ChatGPT and GPT models, Claude, Gemini, DeepSeek, Llama and other current generative-AI systems.
Explainable AI insights
Go beyond a headline score with analysis intended to help explain why text may have been identified as AI-generated.
Edited and mixed AI text
Detection is designed to recognise AI-like patterns even where generated material has been mixed with human writing or subsequently edited.
30 supported languages
The AI detector supports 30 languages, with the document language detected automatically.
No subscription required
PlagPointer is pay as you go. See the exact credit requirement before you start, and keep unused credits for another day.
A setting most checkers hide
Choose your AI detection sensitivity
There is no single threshold that is ideal for every job. PlagPointer lets you decide whether false-positive caution or more aggressive detection matters most for the text you are checking.
1
Extra Safe
Most cautious
Designed to minimise false positives. Best suited to looking for AI-generated text with little or no human modification.
False-positive rate 0.009%
False-negative rate 1.36%
Default
2
Balanced
Recommended for most checks
Balances AI detection with a very low false-positive rate. Designed to handle a moderate amount of human modification.
False-positive rate 0.026%
False-negative rate 0.79%
3
Extra Sensitive
Most aggressive
Designed to flag more heavily modified AI writing, including text passed through “humaniser” or text-spinner style rewriting.
False-positive rate 0.05%
False-negative rate 0.53%
These figures come from the underlying detection engine’s published V10 testing. Results can vary by document, language, model and writing style. See the published testing methodology.
How it works
What does an AI checker look for?
The underlying detection technology evaluates linguistic and statistical patterns associated with human and machine-generated writing. These can include the predictability and structure of language, patterns across sentences and phrases, and signals learned from large sets of human-written and AI-generated material.
AI detectors do not look inside somebody’s ChatGPT account and they do not recover a secret record of who typed what. They analyse the submitted writing itself.
PlagPointer also gives you explainable AI analysis, which can provide additional context around why material was flagged rather than leaving you with an unexplained percentage.
The important bit
“Was this written by AI?” is not a yes/no question
A detector estimates whether writing resembles AI-generated text. It cannot establish authorship as a matter of fact.
Use the result as one piece of evidence alongside drafts, sources, version history, assignment rules and the writer’s own explanation.
Accuracy without the sales fog
How accurate are AI detectors?
Accuracy depends on the detector, the model that produced the text, document length, language, editing and the type of writing being checked. That is why a single headline percentage is never the whole story.
Published provider testing
In V10 testing, the underlying engine behind PlagPointer reported a 0.026% false-positive rate and 0.79% false-negative rate for its default Balanced sensitivity. Extra Safe reduced false positives further; Extra Sensitive reduced false negatives at the cost of a slightly higher false-positive rate.
Independent research can be encouraging
A 2026 peer-reviewed study comparing eight free AI detectors on scientific articles reported that the same underlying engine behind PlagPointer produced the highest mean score for the 12 AI-generated articles tested: 99.6/100.
But results vary with the test
Another 2026 higher-education study found substantial under-detection by several well-known AI detectors on some newer fully AI-generated and humanised academic texts. That is a useful reminder that no detector should be treated as conclusive proof.
Our approach: use the strongest available detection signal, show the customer meaningful controls, and be clear about the limits of what an AI score can establish.
Two different checks
AI detector vs plagiarism checker
AI detection and plagiarism detection answer different questions. A document can be original but AI-generated, copied but human-written, both, or neither.
| AI detector | Plagiarism checker | |
|---|---|---|
| Main question | Does this writing resemble AI-generated text? | Does this writing match material found elsewhere? |
| Looks for | Statistical and linguistic patterns associated with AI writing | Matching, near-matching and paraphrased source material |
| Useful for | AI-assisted writing review, academic integrity, editorial checks | Source attribution, copied material, similarity and citation review |
| Result means | An estimate that should be interpreted in context | Evidence of textual similarity that still needs human review |
If you need an AI plagiarism checker, PlagPointer can run AI detection and plagiarism checking in the same workflow. Learn more about our plagiarism checker.
Different people, different reasons
Who is an AI writing detector useful for?
Students
Check how your own essay or assignment may be interpreted before submission, especially if you have used legitimate AI assistance, rewriting or grammar tools.
Teachers and lecturers
Use AI detection as one signal when reviewing student work, then consider drafts, citations, writing history and the student’s explanation before drawing conclusions.
Writers and editors
Review articles, contributed content and commissioned copy for signs of undisclosed AI-generated or heavily AI-refined writing.
Businesses and publishers
Add an AI-content check to editorial, recruitment, compliance or quality-control workflows where knowing how material may have been produced matters.
Three steps
How to use the AI detector
- Upload your document
Choose the file you want to check. AI detection needs at least 350 words. - Choose your AI sensitivity
Balanced is the default. Select Extra Safe or Extra Sensitive when the context calls for it. - Review the result in context
Use the score and explanations as evidence to investigate, not as an automatic verdict.
Why scores disagree
Why can two AI checkers give different results?
Different tools use different training data, models, thresholds and definitions of what counts as AI-generated. Some are deliberately cautious to reduce false positives; others are tuned to flag more heavily edited AI text.
Text length, language, formatting, paraphrasing, mixed human/AI authorship and newer model outputs can all affect a score. That is why PlagPointer gives you a choice of sensitivity rather than pretending that one threshold suits every use case.
It also means your PlagPointer result should not be expected to reproduce the exact percentage shown by Turnitin, Grammarly, GPTZero, QuillBot or another AI checker.
Looking for the “best AI detector”?
Look for evidence, not just a big percentage
- Published methodology and testing
- Low false-positive rates
- Testing on current AI models
- Clear limitations
- Useful explanations, not just a score
- Appropriate privacy controls
Private by default
Your work stays yours
We do not notify your university, school, tutor or employer that you have used PlagPointer. Your document is not added to the shared comparison database unless you deliberately choose that option, and that option is off by default.
Frequently asked questions
AI detector FAQs
No. PlagPointer is pay as you go rather than an unlimited free AI checker. You can see the exact credit requirement before anything is deducted, and unused credits do not expire.
The underlying detector is designed to identify writing associated with major generative-AI model families, including ChatGPT/GPT models, Claude, Gemini, DeepSeek and Llama. AI models continually change, so no detector can promise perfect detection of every output from every model.
Accuracy varies with the detector, model, language, text length and how much the writing has been edited. PlagPointer’s underlying engine publishes strong testing results, but independent studies also show that AI-detector performance can change substantially with the dataset and generation method. Treat the result as a signal, not proof.
They can detect some modified AI writing, but detection generally becomes harder as generated text is extensively rewritten. PlagPointer’s Extra Sensitive setting is specifically designed to look more aggressively for heavily edited, humanised or text-spinner-style AI content.
False positives can happen because detectors classify patterns rather than knowing who actually wrote the text. Formulaic, highly structured or unusually predictable human writing can sometimes resemble patterns found in AI-generated material. Students using grammar checkers and writing improvers may similarly find their own work flagged as AI as it can make the work ‘too perfect’. If a human-written document is flagged, review the highlighted material and wider evidence rather than assuming the score is conclusive.
There is no single AI checker used by every university, school or teacher. Institutions choose different products and may use different thresholds or policies. More than 1,000 universities use the same engine on which PlagPointer is built. PlagPointer does not share your scan with any university. If the question matters for an assessment, check the institution’s current academic-integrity and AI policy rather than assuming one detector represents every university.
Not necessarily. Different detectors use different models, training data and thresholds, so the same document can receive different scores. A PlagPointer result should not be treated as a prediction of the exact percentage another service will show.
PlagPointer requires at least 350 words for AI detection. Longer documents generally provide more linguistic evidence for a detector to analyse than very short snippets, resulting in greater accuracy.
No. An AI detector can identify patterns associated with AI-generated writing, but it cannot prove who authored a document or whether a particular use of AI breached a rule. High-stakes decisions should consider additional evidence and the relevant policy.
An AI detector estimates whether writing resembles AI-generated text. A plagiarism checker compares writing with sources to identify matching or closely related material. They answer different questions, which is why PlagPointer can run both checks together.
AI checkers use machine-learning models trained on examples of human and AI-generated writing. They analyse linguistic and statistical patterns in the submitted text and estimate how closely those patterns resemble generated material.
Ready to check a document?
Run an AI content check with the sensitivity you choose
Start with Balanced for most documents, or choose a more cautious or more sensitive model in the advanced settings.