AI Detector: Free AI Checker for ChatGPT, Claude & Gemini
Check if text was written by AI in seconds. Paste up to 3,000 words and get an AI score, a likely range and every sentence marked.
- Free, no sign-up
- 40 to 3,000 words
- 17 languages
- Text isn't stored
Or drop a file anywhere in this box
Your result will appear here
You'll get an AI-likeness score, a likely range, a chart of every sentence and what pushed the score up or down.
More free writing tools
WrittenCheck AI detector, in short
WrittenCheck is a free online AI detector. It estimates how likely it is that a text was written by an AI tool such as ChatGPT, Claude or Gemini, and shows which sentences read most like AI.
- Price
- Free, no sign-up
- Text per check
- 40 to 3,000 words
- Daily limit
- 200 checks
- Languages
- 17
- Result
- Score, range, confidence and marked sentences
- Your text
- Checked in memory, never stored
How to check if text was written by AI
Three steps, and most checks take under a second.
Paste the text
Paste at least 40 words. A few paragraphs work better than one, because the AI checker has more to compare. For a result worth quoting, use a few hundred words.
Pick the language
Leave it on "Detect language", or choose it yourself if the text mixes languages.
Read the result
Look at the score, the likely range and the sentence chart. The marked sentences show where the AI-like writing is.
What your AI score means
The score runs from 0 to 100. Higher means the text reads more like AI-generated writing. These are the bands the detector itself uses.
The wording varies the way people's writing usually does.
Some parts read like AI and some don't. This often happens with edited AI drafts or very formal writing.
Most of the text matches patterns we see in AI writing.
Next to the score you'll see a likely range, such as 86 to 100. No AI detector is exact, so the range shows where the true value probably sits. The confidence tells you how sure the check is. Low confidence usually means a short text, or a text that sends mixed signals.
Detect ChatGPT, Claude and Gemini writing
People search for a ChatGPT detector, but students and writers use many AI tools. WrittenCheck works as a ChatGPT detector, a Claude detector and a Gemini detector at the same time, because it looks for the patterns these tools share rather than the habits of one of them.
It tells you how much a text reads like AI. It doesn't tell you which tool wrote it, and no detector can do that reliably.
How does an AI detector work?
An AI detector compares a text with large sets of writing known to be human or AI-generated. AI tools tend to pick the most likely next word, so their writing is smooth and even. People write less evenly.
WrittenCheck runs its own models on its own server. A deep language model, trained on human and AI writing, scores English and 16 other languages. If that server is busy or offline, our built-in model answers instead, so every check still gets a result. Each sentence is then checked on its own. Your text isn't sent to ChatGPT or any other AI service. Read how WrittenCheck works.
How accurate is this AI checker?
Every AI detector makes mistakes. Here's what our tests show and where it's weakest.
Tested on unseen text
In our own held-out test of 14 October 2026, on 15,089 texts in 16 languages other than English that the model never saw in training, it caught 96.8% of the AI writing and wrongly flagged 0.17% of the human writing. See the figures for each language.
Where it struggles
Short texts, AI drafts a person has rewritten, and AI text written in an unusual style. Very formal human writing can also score higher than it should.
Getting better
We retrain the model as new AI tools appear and add new kinds of writing to its training data.
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An AI detector in 17 languages
It picks the language for you, or you can choose it. Tagalog (Filipino) is the newest, with its own Tagalog AI detector page. Other languages don't have their own model yet, so results for them are much less reliable.
Free, private, with fair limits
- Each check takes 40 to 3,000 words. Under 80 words the result comes with low confidence and a wide range, so use a few hundred words when you can. For a longer document, check it in parts.
- You can run up to 8 checks a minute and 200 a day. These limits keep the free AI detector fast for everyone.
- Your text is checked in memory and then thrown away. We don't save it, log it or use it for training. See the privacy policy.
Guides that use the AI detector
Plain articles from the WrittenCheck blog.
AI Hallucination: Real Examples, Causes and How to Fact-CheckAI chatbots sometimes invent facts, quotes and sources with total confidence. Here's why it happens, real cases, and a simple routine to…
How to Write a Thesis Statement (With Weak vs Strong Examples)A thesis statement is one arguable sentence that answers the question your essay asks. Here's how to build one step by step, with worked…
AI Watermarking: How AI Watermarks Work and Where They FailA plain-English guide to AI watermarks in text and images, how they're detected, where they break down, and how they differ from AI detec…
AI Literacy: What It Is and How to Teach It at Every AgeA teacher's guide to AI literacy, with the main definitions and frameworks, the core skills, activities for each age group and a simple w…
WrittenCheck on your phone
Check text for AI in an app made for Android. Scan a printed page, open a file or share text from another app, then see every sentence marked.
- Scan a printed page with your camera
- Open TXT, DOCX and PDF files
- Share text into it from any app
- Your history stays on your phone
What people say about WrittenCheck
Reviews from people with a WrittenCheck account. We publish good and bad reviews alike.
AI detector questions
Is this AI detector really free?
Yes. WrittenCheck is a free AI detector with no paid plan and no sign-up. You can run up to 200 checks a day, each up to 3,000 words.
How do I check if text was written by AI?
Paste at least 40 words into the box at the top of this page and press Check text. You'll get an AI-likeness score from 0 to 100, a likely range, a confidence level and every sentence marked by how AI-like it reads.
Can it detect ChatGPT, Claude and Gemini?
It looks for writing patterns that are common in text from AI tools such as ChatGPT, Claude and Gemini. It doesn't tell you which tool wrote a text, only how much the writing reads like AI.
How accurate is this AI checker?
It's right most of the time on clear cases, but it does make mistakes in both directions. In our own held-out test of 14 October 2026, on 15,089 texts in 16 languages other than English, it caught 96.8% of the AI writing and wrongly flagged 0.17% of the human writing. In every one of those languages it flagged 0.69% or less of the human texts and caught 92% or more of the AI texts. It does worse on short texts, edited AI drafts and AI text written in an unusual style.
How does an AI detector work?
An AI detector compares a text with large sets of writing known to be human or AI-generated. On WrittenCheck, a deep language model trained on both kinds of writing scores the text. If it's busy or offline, our built-in model looks at word choice, short phrases and sentence rhythm instead. Either way you get a score for the whole text and for each sentence.
Can AI detectors be wrong?
Yes. Every AI detector can be wrong, including the big names. Human writing that's very formal or simple can be flagged, and AI text that a person has rewritten can be missed. Treat a score as a pointer, not proof.
What AI detector do colleges use?
Many colleges use the AI writing check built into Turnitin, and some teachers use other tools as well. WrittenCheck isn't connected to Turnitin and can't show you a Turnitin score. It's a separate free check you can run yourself.
What is the best free AI detector?
No AI detector is perfect, so look for one that's free to use properly, shows which sentences it flagged, gives a range instead of one number and is honest about its mistakes. WrittenCheck was built to do all four.
Can I use the score to accuse a student of cheating?
No, it shouldn't be used that way. A detector can be wrong about an honest student, and writers using a second language are more at risk. Use the marked sentences to start a conversation, and look at drafts, notes and the student's other work.
Do you store the text I paste?
No. The text is checked in memory and discarded when the check ends. We don't keep a copy, log it or use it to train the detector.
Why do I need at least 40 words?
Short texts don't carry enough pattern for a fair guess. Below 40 words the results swing too much to be useful, so the detector won't run. From 40 to 80 words it runs, but the result is marked low confidence and has a wide range. For a result worth quoting, check a few hundred words.
Is this a plagiarism checker?
No. WrittenCheck doesn't compare your text with web pages or papers. It only looks at how the writing reads.
What languages does it support?
Seventeen: English, Arabic, Chinese, French, German, Hindi, Indonesian, Italian, Japanese, Korean, Portuguese, Russian, Spanish, Tagalog (Filipino), Thai, Turkish and Urdu.
Last updated 14 October 2026.
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