See which sentences and phrases look AI-generated. Paste text, upload a file or take a photo of handwritten work.
Featured on There's An AI For ThatDetects ChatGPT, Claude, Gemini, DeepSeek, Llama, Grok and moreNever used to train AI
A good AI checker gives you more than a number. Clasa shows you where to look in an essay, research paper or article, and why.
My dad drove two hours to work. This paradigm shift catalyzed an unprecedented change. Ultimately, resilience remains essential.
Clasa highlights each sentence that looks AI-generated. Phrase view goes further and marks the exact words behind each flag.
…every spring she let me choose one new seed to plant.
Take a photo of a handwritten page, check the text Clasa reads from it, and run the same check.
Economic shifts reshape communities in lasting ways.
Add your notes to the report, or grade the same essay with your rubric, all in one place.
The result is a likelihood, not a verdict. Use it to decide where to look more closely.
A free AI content detector for teachers, students and writers, from your first check to your final review.
Overall score
Every check gives you one AI likelihood score for the whole text, from 0 to 100%. Each sentence also gets its own likelihood, so you can point to the exact lines that raised the score.
Any writing
Use it as an AI detector for essays, homework, research papers and college application essays, or for articles, blog posts and cover letters. Upgrade when you need to check longer texts.
Any format
Paste text, upload a PDF, Word or text file, or take a photo of a page. Clasa pulls out the text for you, and you can fix anything before the check runs.
Multilingual
Check writing in English, Spanish, French, German, Portuguese, Chinese, Arabic and 20 more languages. Clasa picks up the language on its own.
Privacy
We never use your text to train AI models. Checks you run while signed in are saved in your documents, and you can delete them at any time.
Free to start
Run your first checks without an account. Sign up to save your checks, and upgrade when you need more.
Checking text with this free AI detection tool takes three steps and no setup.
Type or paste your text, upload a file or take a photo of a handwritten page. For photos, check the text Clasa reads and fix any misread words before you go on.
Select Check for AI. In a few seconds, you’ll see an overall AI score and the sentences that look AI-generated. Switch to phrase view to see the exact words behind each flag.
Read the highlights in context. If you know more than the tool does, relabel a sentence or add a note. Then download the report, or open the Grading tab to score the same text against a rubric.
Clasa works as a handwritten AI detector: it checks a photo of a handwritten page the same way it checks typed text.
Many teachers have moved essays back to paper to limit AI use. But a handwritten page only shows who held the pen. A student can generate an essay with AI at home and copy it out by hand. Clasa checks the words, not the handwriting.
Writing done in class, under supervision, is still the strongest evidence of who wrote it. For handwritten homework and take-home essays, a check gives you a starting point for a conversation, not a verdict.
Fixing the text matters. A misread word can change a sentence, and the result. Each check reads one photo, so check a longer essay one page at a time.
For a clear photo
An AI detector shows which parts of a text read like AI writing. It can’t tell you who wrote it, or why.
A score of 72% means the detector finds the whole text 72% likely to be AI-generated. It doesn’t mean 72% of the text came from AI, and it says nothing about the writer’s intent.
Each color labels one sentence. Blue means the signals are unclear, neither clearly human nor AI. Treat any highlight as a reason to reread, not as proof.
No AI detector is 100% accurate, Clasa included. The style and length of a text, and the AI model behind it, can all affect the result. A high score doesn’t prove AI use, and a low score doesn’t prove human writing. Formulaic or highly polished writing can look AI-generated. Very short texts give any detector little to go on.
A score should never be the only evidence behind a decision.
Add your own judgment to the AI detection report before you share it. The detector’s first pass and your review stay together in one document.
Mark a highlighted sentence as human-written when you have context the detector doesn’t, such as a line the student wrote in class.
Comment on the whole report or on one sentence, such as “Drafts shown in class.”
Word the overall finding to match what you concluded after your review.
Your notes sit next to the detector’s original result, so anyone reading the report sees both. Editing is for recording an informed review, not for changing a result you don’t like.
Two sentences were flagged as AI-generated. The opening line was written in class, so I marked it human-written.
Use Clasa as a ChatGPT detector, or to check work drafted with Claude, Gemini and other AI writing tools.
One draft can mix human and AI text. Clasa marks it sentence by sentence, so you can see where each part sits.
The same check runs in Spanish, Arabic, Japanese and 24 more, and Clasa spots the language for you.
One check
ChatGPT
Claude
Gemini
DeepSeek
Llama
Grokand moreYou don’t have to know which AI tool was used. One check looks for patterns common in AI writing.
Whatever tool was used, read the result alongside the writing itself.
Students checking their own work, teachers reviewing a class set, and anyone who needs to know where a piece of writing came from.
Worried your essay will be flagged? Use Clasa as an AI detector for students and check your work before you hand it in, so there are no surprises.
An AI detector for teachers that works on typed and handwritten essays. Check homework, add notes to the report, then grade the same work with your rubric.
Use one AI checker for teachers across a department, so everyone reads results the same way and every student gets a fair chance to explain.
An AI detector for writers and editors. Check drafts and freelance submissions, and add notes where a flagged passage needs context.
Run articles through an AI content detector before you publish, next to editing and source checks. It won’t tell you if content is good or will rank.
Use an AI text detector on cover letters, applications and reports. Style alone won’t show who wrote a document, so treat the result as one input.
Every plan includes AI detection and essay grading with your rubrics. Pick the one that matches how much you check.
For solo teachers who grade regularly with AI-assisted feedback.
Included in this plan
For educators grading at volume with unlimited chats and richer history.
Included in this plan
For teams who split grading across educator seats with pooled quotas.
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Create a free account first — no payment until you upgrade.
Many teachers now set an AI rule for each assignment, so a fair grade needs two answers: how the essay was likely written, and how good the writing is. Once the AI check is done, grade the same text with your rubric. You’ll get a score and feedback next to the AI result, with no need to paste it again.
Quick answers about using a free AI detector, reading your results and keeping your text private.
An AI detector estimates how likely it is that a text was written by an AI tool such as ChatGPT. Clasa scores the whole text and each sentence, so you can see which parts to read more closely.
Yes. You can run your first checks free, without an account. Upgrade when you need longer texts, more checks or phrase highlights.
Paste the text, upload a file or add a photo of a handwritten page, then select Check for AI. Read the score and the highlighted sentences next to drafts or earlier work before you decide anything.
Yes. One check covers ChatGPT, Claude, Gemini, DeepSeek, Llama, Grok and other models, so you don’t need to know which tool was used. The result won’t say which model wrote the text.
No. Copying AI text onto paper keeps the same words, and the check looks at the words. Take a photo of the page and check it like typed text.
It works in 27 languages, including English, Spanish, French, German, Chinese and Arabic. Clasa detects the language of your text automatically.
It looks for patterns common in AI-generated writing and gives each sentence a likelihood. Together, those sentence scores make up one overall score for the text.
Clasa is built to spot writing from both closed and open-source AI models, from ChatGPT, Claude and Gemini to Llama and DeepSeek. It scores every sentence, not just the whole text, so even a few AI-written lines in a human essay can stand out. The check works the same way in all 27 languages it supports. Like any AI detector, it gives a likelihood, so read flagged sentences in context before you act.
Yes. Each sentence gets its own label, so you can see where human and AI writing may mix within one piece.
No, not on the score alone. Talk with the student, look at their drafts and earlier work, and follow your school’s policy.
Some human writing reads like AI, especially very formal or formulaic text, writing smoothed by grammar tools and short pieces. Detectors can be wrong, so share your drafts and version history to show how you wrote it.
Yes. You can relabel sentences, add notes and reword the summary. The detector’s original result stays in the report next to your changes.
Your text is never used to train AI models. Checks you run while signed in are saved in Documents until you delete them, and checks run without an account aren’t saved. Read our privacy policy for details.