Loading tools
Loading tools
Loading tool
Check if text was written by AI with a sentence-by-sentence heatmap.
An AI detector is a free tool that tells you if a piece of writing was made by a human or an AI like ChatGPT. You paste in text, and it reads the writing patterns and gives you a score plus an easy to read report.
It helps teachers check student work, writers polish content before publishing, and SEO teams keep their sites safe from Google penalties. Our detector goes further than most with a sentence-by-sentence heatmap and a guess at which AI model likely wrote the text.
Paste any text into the box. You can also upload a PDF, DOCX, or TXT file, or drop in a web page URL.
Our tool checks word patterns, sentence rhythm, and meaning. It runs two checks at the same time to catch AI content other tools miss.
See an overall verdict, a confidence score, a color-coded heatmap for each sentence, and the most likely AI model that wrote it.
Every sentence gets a color. Green, yellow, or red. Click any sentence to see why it scored that way.
Human Written, AI Assisted, or AI Generated. A useful answer, not a basic yes or no.
Guesses which family of AI tool wrote the text based on common writing-pattern fingerprints.
See perplexity, burstiness, vocabulary variety, and sentence uniformity for every scan.
Paste text, upload a PDF or DOCX, or submit a URL. We pull the text out for you.
Statistical checks run alongside AI analysis. Two views of the same text, fewer false positives.
Ship writing you know reads as human before a teacher, client, or editor ever sees it.
See the exact sentences that look AI generated and rewrite just those parts.
A full scan of a 5,000 word essay finishes in under 3 seconds.
We do not store your text or use it to train any model. Every scan runs on an encrypted connection.
Check student submissions before grading. The heatmap shows which sections need a closer look.
Self-check essays before you turn them in. Make sure your writing sounds like you.
Keep published articles under the AI thresholds clients and ad networks now require.
Audit site copy at scale. Google now ranks detectable AI content lower in competitive niches.
Screen cover letters and applications to spot candidates who put in real effort.
Flag AI generated filings, contracts, or testimony where human authorship is a rule.
These two tools answer different questions. An AI detector asks “was this written by AI?”. A plagiarism checker asks “was this copied from somewhere else?”. Smart writers use both.
| Feature | AI Detector | Plagiarism Checker |
|---|---|---|
| Main purpose | Checks if text was written by AI | Checks if text was copied from other sources |
| How it works | Reads language patterns and predictability | Matches text against a database of published content |
| What it catches | AI written text even if fully original | Copied or paraphrased text from known sources |
| Common false flags | Very formulaic human writing may flag | Common phrases and quotes may flag |
| Use them together | Yes. Different checks that complement each other | Yes. Neither tool replaces the other |
AI writes by picking the most likely next word over and over. The result is text that feels a bit too predictable, like it never surprises you. Humans make odd word choices, drop in idioms, and switch tone mid-sentence. Our detector measures how predictable each part of the text is. Too predictable is a red flag.
Humans mix short punchy sentences with longer ones that carry more detail. AI tends to write sentences that are all about the same length. We measure how much the sentence length changes across your text. A flat rhythm often means AI. A lively, uneven rhythm usually means human.
AI models reuse the same favorite phrases and transitions. They also avoid rare or specialized words unless you specifically ask for them. We check how varied your word choices are and look for repeating patterns. When we combine these checks with the other signals, we catch AI writing that a single metric would miss.
Molixa builds 60 plus free AI tools for students, writers, and busy professionals. No signup to try any of them. No credit card for the free tier. Built to feel fast and stay out of your way.
Try our other popular tools:
The AI Content Detector page is built, reviewed, and maintained by the Molixa team. We use the tool we ship and update the docs when the behavior changes.