Free Claude AI detector to check any text
A free Claude AI detector for any text. Paste it, upload a file, or drop in a link.
Check your textHow to read your AI detector score
The AI detector gives you a single number from 0 to 100. It is the estimated chance that AI wrote the text, not a yes or no. Here is what each band means.
Probably a person
Reads like human writing. We did not pick up the patterns a model tends to leave behind.
Hard to say
Some of it leans one way, some the other. Read it yourself before you draw a conclusion.
Probably AI
This has the marks of machine-written text. Read it closely before you conclude anything.
How the Claude detector works
Three steps, a few seconds, no setup.
Add your text
Paste it, upload a Word or PDF file, or drop in a link to the page you want to check.
We check the patterns
The model weighs your text against the way Claude writes and the way people write.
Read the score
You get a number from 0 to 100 and a plain read on how likely AI was involved.
What gives Claude away
Claude, from Anthropic, tends to write in tidy, well-mannered paragraphs. It signposts its structure, opens with clear topic sentences, and weighs both sides before landing somewhere measured. The tone stays even and considerate from start to finish.
People are less consistent. They drift, they get blunt, they leave a thought half finished. Our Claude AI detector is trained on Claude's output set against human writing, so it learns to read that steady, balanced rhythm rather than the meaning of the words.
How accurate is this Claude AI detector?
On clean test text it is right most of the time, comfortably above nine in ten. Real writing is messier, so treat the score as a strong hint, not a fact. Anyone promising certainty about AI text is overselling.
Short passages and edited drafts are where it slips. Once a person rewrites Claude's output or runs it through a paraphraser, the even rhythm breaks up and the tells fade.
Claude 3, Claude 4 and the 4.x line
The detector covers Claude across its versions: the Claude 3 family (Haiku, Sonnet and Opus), the 3.5 and 3.7 Sonnet releases, the Claude 4 generation that arrived in 2025, and the steady stream of 4.x point releases through 2026 up to Opus 4.8. Newer Claude models write with more range, so very recent text can sit closer to the borderline.
- Mar 2023 Claude 1
- Jul 2023 Claude 2
- Mar 2024 Claude 3 (Haiku, Sonnet, Opus)
- Jun 2024 Claude 3.5 Sonnet
- Feb 2025 Claude 3.7 Sonnet
- May 2025 Claude 4 (Sonnet, Opus)
- Sep 2025 Claude Sonnet 4.5
- Oct 2025 Claude Haiku 4.5
- Feb 2026 Claude Opus 4.6 and Sonnet 4.6
- Apr 2026 Claude Opus 4.7
- May 2026 Claude Opus 4.8
Where your text goes
The check happens in memory on our own server. As soon as you have a score, your text is dropped. No logs, no database, no training set.
There is no account holding a history of your checks either.
Claude AI detector FAQ
Is the Claude AI detector free?
Yes. The whole tool is free, with no account and no cap on how many checks you run.
Does it work on Claude 4?
Yes. It reads output across Claude's versions. The newest releases are harder to flag, so weigh borderline scores carefully.
Will it catch Claude text I edited?
Sometimes. Light edits often slip through. Heavy rewriting or paraphrasing can hide the tells well enough to fool it.
Can I upload a file or a link?
Yes. Upload a Word or PDF file, or paste a web address, and we'll pull the text out for you.
Does it work on ChatGPT or Gemini too?
Yes. The same model covers ChatGPT, Gemini and others. For general use, try the main AI detector.