An AI detector for teachers who need to be fair

IsThisAiWritten is a free AI detector for teachers that checks student work inside your own browser: no account, no per-class limits, and no essay uploaded to anyone. Paste a submission below to see where to look and what to ask, then let the conversation with the student, and the student's own evidence, do the rest.

What an AI detector for teachers can tell you about student work

Start with the fact that matters most for marking. Like any detector, it can be wrong in both directions, so treat a result as a reason to look closer, not as proof. What it gives you is a place to start: an outcome, the AI-likeness line and a sentence map showing which passages to read first. Our methodology page explains how it is tested.

If you teach students who write in an additional language, keep in mind that research on detectors has found plain, second-language English is flagged more often. The same goes for any class taught to write to a strict template, since formal, formulaic writing can look statistically like AI.

A workflow for checking a submission

1. Remove the cover sheet, bibliography and long quotations, and paste the student's own prose into the box above. Aim for 150 words or more.
2. Press Check for AI.
3. Note the outcome, the confidence word and the AI-likeness line. If your school wants a record, download the result as JSON or print it to PDF.
4. If the outcome is AI or Mixed, read the passages the sentence map marks highest, in context, before deciding anything.
5. Compare with what you already know: the student's in-class writing, earlier drafts and the brief they were given.
6. If you still have concerns, talk with the student before reaching any conclusion.

What to do with an “AI” result

Treat it as a question. Tell the student you used a detector, show them the result and give them a real chance to respond. Ask for drafts, notes and the document's version history; many writing tools keep one automatically. Ask them to talk you through one argument in the essay, or to extend it by a paragraph while you wait. A student who wrote the work can usually do this without much trouble. A student who can't may still have written it, so keep the conversation open-ended.

A flag with nothing else behind it should not lead to a penalty. Never use a detector result as the only evidence against a student.

What to do with “Inconclusive” or “Mixed”

Inconclusive means the detector won't guess, and it says why: the text was too short, it wasn't in English, or the evidence pointed both ways. Treat it as no information. Resist re-running trimmed versions of the essay until something flags; that is fishing, and it will eventually catch something by chance.

Mixed points you at one stretch of the essay, so read that passage before anything else. It might be a pasted-in paragraph, but it can just as easily be the most formal writing in the piece, such as a summary of the set reading. Ask the student how that section came together.

Why local checking helps with student privacy

Many schools limit which outside services can receive student work. Because this detector runs in the browser, the essay isn't sent anywhere or added to a database, and there is no account linking checks to you or your students. Anyone at your school can confirm this using the steps on the private AI detector page. Check your institution's policy all the same.

Limits to keep in mind

Short answers are hard to judge: the detector needs 50 words for any result and 150 for a firm one. The detector reads English only. Treat a result as a starting point for a conversation, which is the only fair way to use an AI detector. The signs of AI writing post covers what to look for beyond a score.