Who this is for
This page is for two people who often end up on opposite sides of the same desk. The first is a student who wrote an essay, maybe with some help from a grammar tool, and wants to know how it will read to a teacher who runs it through a detector. The second is a teacher, tutor or teaching assistant with a pile of essays and a feeling about one of them.
Both deserve the same thing: an honest reading with its uncertainty drawn, not a verdict. A student should not be told they cheated by a number. A teacher should not be told a number settles anything. The checker above gives you a probability for the whole essay, a reading for each paragraph and the plain-language reasons behind each one, so you can judge for yourself.
What to paste
Paste the essay as it will be handed in, from the first line of the introduction to the last line of the conclusion. Leave out the title page, the bibliography and any quoted passages longer than a few lines, because a block of someone else’s words is not the writing you want read. Keep the paragraph breaks: we read paragraph by paragraph, and a wall of text with no breaks gives you only one reading.
If the essay is longer than 10,000 characters, check it in two parts, split at a paragraph break. Each part gets its own reading.
How to read the result
Start with the sentence, then the number, then the bracket. The bracket under the number is the likely range; when it is wide, the essay is short or the model is unsure, and the number deserves less weight. Then look at the paragraphs. A school essay often has a personal opening that reads human and a formal middle that reads closer to AI, because textbook structure and AI writing share habits. That pattern on its own says very little.
Select an amber paragraph to see why it leans AI. Each reason is something you can check with your own eyes: very even sentence lengths, stock phrases such as “Furthermore” and “In conclusion”, a tidy template shape, words that repeat more than in the rest of the essay. A student taught to write five-paragraph essays will produce several of these honestly.
Drafts and version history matter more than any score
If you are the student, your drafts are your strongest evidence. Most document editors keep a version history that shows the essay growing over days, with false starts and rewritten sentences. Notes, outlines and the sources you read tell the same story. Keep them.
If you are the teacher, ask for them. A conversation about how the essay was written, what the student found hard and what they would change, will tell you more than a detector. Use the result to decide which paragraphs to talk about, not what to conclude.
Limits of the tool
This checker reads English only. It does not compare the essay with other sources or look for copied passages. It cannot tell an essay that AI drafted from one that AI only polished, and it cannot tell a careful human writer from a model on every paragraph. It gives a probability, never proof, and no grade or accusation should rest on it alone.