Essays are the text people most often bring to a detector, and the situation around them is usually a teacher and a student rather than a reader and a document. That changes what a result is good for. This page is about the essay case specifically: who may check what, why short answers are the riskiest thing you can check, what a formulaic essay structure does to the score, and how to read one real result.
AI Detector Checker returns a 0-100 AI-writing signal score, a score stability range and one of three bands for English text of at least 100 words. It never identifies a model, never marks a sentence, and is never enough on its own for a decision about a person.
Who may check what
Three situations, three different answers.
- Your own essay, before you submit it. Nothing to weigh up. Check it if the result is useful to you, and ignore it if it is not.
- A student’s essay, as a teacher. Legitimate as triage — a way of deciding which of thirty submissions is worth reading closely — provided the result never leaves your own reading. It is not evidence, it does not go in a file, and it does not start a disciplinary process. If your institution has a policy on AI-detection tools, that policy decides, not this page.
- Someone else’s essay, without their knowledge, in order to accuse them. This is the use we ask you not to make of the tool. A score cannot support an accusation, and using one that way puts the burden of disproving a machine on a person who has no way to do it.
The evidence that actually settles authorship is not a score. It is the draft history: document version history, comments and their timestamps, notes, search history, the outline that preceded the essay, and the student’s own account of how they wrote it. A five-minute conversation about the argument tells you more than any detector, and a student who worked through the material answers immediately.
Why short answers are the risky case
The engine holds shorter texts to a stricter bar because short human writing is easier to misread — and it is still less reliable there. In our sealed test, human texts of 100 to 149 words received a wrong AI signal about 2.4 in every 100 times (14 of 586). At 150 words or more the same measurement was about 2 in every 1,000 (4 of 2,343). That is more than a tenfold difference, and it falls entirely on the length of text that short-answer questions, exam responses and reflective paragraphs produce.
The practical consequence for a class set: if you check thirty 120-word answers, you should expect roughly one wrong AI signal on honest work by arithmetic alone, before anything about the writing is considered. That is not a reason to distrust the tool; it is a reason not to check texts that short, and never to treat a single short result as a finding. Where you can, check the longest piece of continuous prose the student wrote.
What taught essay structure does to the score
Students are taught to write in a way that reduces exactly the variation the classifier measures. A signposted introduction, three body paragraphs of similar length each opening with a topic sentence, transition phrases between them, and a conclusion that restates the introduction: that is a good essay by the standard it is marked against, and it is also uniform sentence length, generic framing and low specificity — three of the things the engine keys on.
So a competent, well-drilled, entirely human essay can land in Uncertain, and sometimes above it. Two things separate that case from a generated one, and neither is in the score: concrete specifics — a named source, a date, a number, a detail from the seminar that nobody else would have written — and uneven effort, where the paragraph the student found difficult reads differently from the one they found easy. Generated essays are evenly good throughout.
What to do with Uncertain
Uncertain is the most common band for essay-shaped writing, and it means the evidence is mixed. It is not a weak accusation and it is not “probably AI”. Edited work lands there, partly drafted work lands there, formal work lands there and second-language English lands there. The correct response is to treat it as no useful answer and go back to the text: read it, ask about it, look at the drafts. If nothing else about the essay concerns you, an Uncertain band on its own is not a reason to act.
A worked reading of one result
A 300-word essay comes back with a score of 74, a stability range of 66–83, the band Uncertain, length band 300–599 words, and the note that at this length about 2 in every 1,000 human texts received a wrong AI signal. Read it in that order.
- The band is the answer, not the number. At 300–599 words the Uncertain band runs from 68 up to 97 on the displayed scale. 74 is near the bottom of it. The band was decided on the internal value, not on the 74.
- The range is wide. 66–83 is 17 points, which says the exact number is soft — it would move if the source families behind the display map were resampled. A 74 with a range of 66–83 is not meaningfully different from a 79.
- The false-flag rate applies to the length, not to this text. 2 in 1,000 is the rate at which human texts of this length were wrongly flagged. This text was not flagged, so the figure is context, not a probability about the essay.
- What to do. Nothing, on this alone. Read the essay for specifics, look at the draft history if you have it, and ask the student about the argument if something else already concerned you.
Running the check, and where to read more
Paste at least 100 words of English prose into the tool on the homepage — it is the same detector everywhere on this site. Paste the body of the essay, not the title, the bibliography or block quotations, and if the essay has distinct sections, check them separately; compare mode takes up to three passages and reports each on its own, never averaged. What an AI detector score means explains the score, the range and the bands in full. If your own essay was flagged, what to do if your text is flagged sets out the next steps. Other content types are on the content-type hub.
Essay detection FAQ
Can a teacher use this to decide whether a student used AI?
No. The result is one review signal about a passage, not evidence about a person, and it is never enough on its own for an academic decision. Use it to decide whether an essay is worth a conversation, then ask about the drafting and look at the revision history.
Why are short answers riskier than full essays?
Because the 100 to 149-word band is held to a stricter bar and is still the least reliable one. In our sealed test about 2.4 in every 100 human texts of that length drew a wrong AI signal, against about 2 in every 1,000 at 150 words or more.
Does a well-structured essay score higher?
Formulaic structure pushes a text towards the patterns the classifier measures: five paragraphs of even length, a signposted introduction and a conclusion that restates the introduction all reduce the variation the engine keys on. Being taught to write that way is not evidence of anything.
What should a student do with a Likely AI-written band on their own work?
Keep the drafts. Version history, comments, notes and search history are the evidence that actually settles authorship; a detector score is not. Read what to do if your text is flagged for the practical steps.
Can I check a classmate’s essay?
Not without their knowledge and a reason. The tool is for your own writing, or for text shared with you for review. Running a check on someone else’s work in order to accuse them is the use this site asks you not to make of it.
Does the detector say which AI model was used?
No. It never identifies a product or a model family. It reports how closely the passage matches the AI writing in its training data, at a threshold that depends on the length of the text.