Felo
Free AI Detector — ChatGPT, GPT-4 & Claude Text Checker
Free AI Detector — ChatGPT, GPT-4 & Claude Text Checker
What is Free AI Detector?
A free AI content detector that scans any text you paste — or upload — and tells you how likely it is to have been written by ChatGPT, GPT-4, Claude, Gemini, or another large language model. Instead of a bare number, you get a 0–100% AI probability score with sentence-level flags and a plain-English reason for every mark, so you always know why a line was flagged.
Key Features
- Score any text 0–100% — one clear AI probability estimate with a verdict band: Very likely AI, Possibly AI, Mixed, or Likely human.
- Flag sentences individually — see exactly which sentences look AI-written and why, with the triggering phrase quoted in plain English.
- Estimate the origin model — learn whether the style points toward ChatGPT/GPT-4, Claude, or Gemini when the signals align.
- Suggest humanizing rewrites — get natural rewrite options for the most heavily flagged sentences so you can revise instead of guess.
- Scan files, no limits — upload .txt, .docx, .pdf, or .md files, or paste text of any length with no word cap and no daily scan limit.
How to Use
- Paste your text — drop in an essay, article, email, or assignment. You can also upload a .txt, .docx, .pdf, or .md file instead.
- Review your report — read the AI probability score, the signal table, and the flagged-sentence list with reasons for each mark.
- Refine if you like — ask for humanized rewrites, rescan a revised version, or scan another document.
Example Use Cases
- Student essay check — paste a draft before submitting to see which paragraphs read as AI-generated, and get rewrite suggestions to make it sound more like your own voice.
- Teacher essay screening — scan a batch of student submissions to spot machine-written assignments early, then double-check flagged sections before any conversation.
- Freelancer client-content review — verify a ghost-written blog post or product description still reads human before you invoice it.
- Recruiter resume & cover letter check — scan a candidate's cover letter for AI-generated boilerplate before an interview.
- Journalist source verification — check press releases and tips for machine-generated filler that could undermine a story.
Tips for Best Results
- Longer text, more reliable score — inputs above 300 words produce steadier results; very short snippets under 80 words get a lower-confidence estimate.
- Paste clean text — remove formatting, links, and headers you don't want analyzed; the detector reads raw words.
- Treat the score as a signal, not a verdict — use the per-sentence flags as your evidence and never make an academic or hiring decision on the number alone.
FAQ
How long can the text I paste be?
There is no word limit. Very long documents are analyzed in full; the report groups flagged sentences by section so it stays readable, and you can ask for a deep dive into any part.
What file formats are supported?
.txt, .docx, .pdf, and .md files. Paste text directly if your file is in another format. If a file fails to parse, the agent tells you and you can paste the content instead.
How accurate is the AI detection score?
The 0–100% score is a probability estimate built from measurable linguistic signals — sentence rhythm, word predictability, formulaic transitions, and template structure. It is transparent (every flag comes with a reason) and calibrated for low false positives on human writing, but it can never prove authorship. For the most reliable result, scan 300+ words.
How does Free AI Detector compare to QuillBot's AI detector?
Both look for AI-generated text, but this agent has no word cap and no daily scan limit — QuillBot's free tier caps scans per day and reserves detailed explainers for Premium. Here, every flagged sentence comes with an explanation and a humanization suggestion at no charge, and you can upload files directly instead of pasting. The trade-off: QuillBot offers a downloadable Premium report and a separate AI image detector, while this agent gives you interactive, explain-everything analysis in conversation.