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Check an essay for AI writing, sentence by sentence

Yes, you can check an essay for AI writing in seconds. Paste it into Winston AI or upload the .docx, and you get a 0–100 human score plus sentence highlights: red for likely AI, yellow for mixed signals. Treat the result as evidence to weigh next to drafts and the writer's other work, never as proof on its own.

  • 99.4% accurate
  • Free to try
  • 14 languages
  • Sentence-level results
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Key facts

  • Winston AI gives every essay a 0–100 human score and highlights each sentence: red for likely AI, yellow for mixed signals.

    Source: AI Detector

  • Anyone can check up to 800 words without an account; texts need at least 80 words to be scored.

    Source: AI Detector

  • AI detection uses one credit per word, so a 1,200-word essay uses 1,200 credits. New accounts start with 2,000 free credits.

    Source: Pricing

What changes when you check essays

  • Essays follow a formula

    A thesis in the first paragraph, three supporting points and a conclusion that restates them is exactly what many assignments ask for. That predictability is also part of what a detector looks for, so a by-the-book essay can pick up yellow sentences with no AI involved.

  • Intros and conclusions are the most generic part

    Opening and closing paragraphs lean on broad statements about society, history or 'today's world'. Expect them to read more machine-like than body paragraphs full of quotes, examples and analysis, and weigh them less.

  • Edited drafts send mixed signals

    An essay a student wrote and then ran through a grammar or rewriting tool often shows yellow, mixed-signal sentences. Whether that was allowed depends on the assignment's rules, not on the score.

  • Quotes aren't the writer's words

    Quoted passages from sources belong to someone else. Read highlights on quotations separately from highlights on the writer's own sentences.

How to check essays

  1. Step 1: Paste the essay or upload the file

    Paste the full text, intro and conclusion included, or upload a .docx. Leave out the title page and the works-cited list: names and citations add noise and use credits.

  2. Step 2: Check the human score and the verdict

    The score runs from 0 to 100, where higher means more human-like, and the verdict sums it up as likely human-written, a mix of AI and human, or likely AI-generated.

  3. Step 3: Read the highlighted sentences in context

    Look at where the red and yellow sentences sit. A red intro around a specific, personal middle tells a different story than an essay that is red from start to finish.

  4. Step 4: Compare with the writer's other work

    Set the essay next to earlier drafts, version history and in-class writing. A result that matches nothing else you know about the writer is a reason to look again, not to act.

  5. Step 5: Save or share the report

    On paid plans you can download a PDF report or copy a share link, so a colleague or the student sees the same highlights you did.

Winston AI is an artificial intelligence essay checker for teachers, students and anyone who reads essays for a living. Paste the essay, see which sentences read as machine-written, and use the highlights to decide what deserves a closer look. This page covers what makes essays tricky to judge and how to read the result fairly.

What an AI essay checker can and can't tell you

An AI essay checker estimates how much of a text reads like machine-generated writing and shows you where. It can't tell you who wrote the essay, which tool was used, or what the student intended. That is why the sentence highlights matter more than the headline number: they point you to the passages worth asking about.

Check for copied text too

AI writing and plagiarism are different problems. On Advanced and Team plans, a plagiarism check compares the essay with web pages and your own library and can leave out quotations and the reference list, so properly cited material doesn't count against the writer.

  • Scan the essays that read unlike the student's usual work first; you don't need to scan everything.
  • Ask students to keep drafts or version history for longer essays.
  • Talk with the student before deciding anything. Our guide on spotting a ChatGPT essay covers what to look for beyond the score.

Questions about checking essays

Still unsure? Browse our guides or ask our team.

Is there a free AI essay checker?

Yes. You can check up to 800 words on our site without an account. A free account adds 2,000 credits, and one credit covers one word, so you can check a few full essays before choosing a plan.

How long does an essay need to be to check it?

At least 80 words. Shorter texts can't be scored, and short answers give any detector very little to judge, so results on short pieces deserve extra caution.

Can it tell which AI wrote the essay?

No. Winston AI estimates whether sentences read as machine-written; it doesn't name the model or tool behind them.

What does a score of 50 mean?

It means the essay shows a mix of human and AI-like signals. Read the highlights to see where the AI-like sentences are, and see how to read an AI detection score for more.

Will a grammar checker make my essay look AI-written?

It can. Light polishing by a grammar or rewriting tool often shows up as yellow, mixed-signal sentences. Keep your drafts so you can show how the essay developed.

Does it check essays in other languages?

Yes. Winston AI detects the language automatically and supports 14 languages, including Spanish, French and German.

Check other kinds of writing

Check your essays now

Paste the text to see which sentences read as machine-written. Sign up free when you want to keep your reports.

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