Free AI Content Detector

What Is an AI Content Detector?

Quick answer: An AI content detector is a classifier: text goes in, one number comes out, and that number estimates how likely a model wrote the text instead of a person. Ours scores pasted text, checks long text in sections and shows an AI probability bar with a verdict. Try it with your own text.

It is free and needs no account. People paste text and ask, "Is this written by AI?" An AI detection tool answers with a number, not a yes or no, and that number is a lead to follow.

How to Check If Text Is AI Generated With This Free AI Detector

To detect AI generated text here, use one box and one button. It takes text only: no file upload, no URL box, no PDF support.

1. Paste your text. The hint reads 50 to 15,000 characters and says the detector is trained on English and wants 300 characters or more. Your text stays in the box after a check.
2. Press Check for AI. The button turns into Checking... and stays disabled. A check takes from several seconds to about a minute, depending on server load: in our tests on October 16, 2026, about 6 to 9 seconds on a quiet server and 21.8 to 58.0 seconds at its busiest, and 17.6 seconds on October 17 at a load average of 11 to 13. Sectioned text takes longer: 3,600 characters took 40.1 seconds at a similar load. A busy detector says so and keeps your text.
3. Read the bar and the verdict. Scroll down to the card headed Result for the AI probability bar, its percentage and one of four verdicts. A long text also gets a bar per section. Check another empties the box.
4. Decide what to do next. Match the percentage to its score band in the next section, then run a second passage before you act.

Before you paste: Use a few paragraphs of prose rather than one line, and only text you wrote or are entitled to check. Then paste your text in the tool above.

How to Read the AI Probability Score

The AI probability on the bar is a confidence score: how strongly the model thinks the pasted text reads as machine written. It is not the percentage of AI in your text, because 850 characters of human writing followed by about 1,100 characters of AI text scored 100. On a long paste it is the average of the section scores. Four verdicts split the scale at 30, 55 and 80, and each score threshold is our own choice.

The same text returns the same score: one text run twice gave 1.5 both times, and the AI blog paragraph that scored 100 on October 16 scored 100 again on October 17. Scores bunch at the ends: 12 of the 15 results in the test table below landed in green or red. Read any AI score next to the text length.

What We Tested: Human, AI and Mixed Text

The live tool returned these scores on October 16, 2026, one run per text plus one repeat. The human texts are public domain works from Project Gutenberg, a 2017 arXiv abstract and a 2013 essay, so none had AI help. An AI chat model wrote the AI samples. This hand-picked set is not a benchmark, and each text is short enough to be scored as one piece.

Of seven human texts, four read as Likely human written, two as Mixed or unclear and one, the Declaration of Independence, as Very likely AI generated at 98.4. Five of six AI texts scored 99.7 or higher, and one scored 14.4. The human and AI mix scored 100, and the hand-edited paragraph fell to 32.4. Misses ran both ways.

Run your own text through this AI content checker, starting with something you wrote before AI writing tools existed.

Limits of This AI Text Detector

A false positive calls human writing AI, and a false negative waves AI writing through. We saw both.

• Long text is checked in sections. The model reads at most 768 tokens at once, which held roughly 3,000 to 4,600 characters of English in our measurements. So the page cuts anything over about 3,400 characters into evenly sized sections, none longer than about 3,000 characters and five at most (3,600 characters become two of about 1,800), and scores each on its own. The card shows each section, the highest one and their average by length. Averages blur things: if three equal sections score 3, 40 and 100, the average is 47.7, Mixed or unclear, although one scored 100. If time runs out, the card scores the sections it reached and says how many characters they cover.
• Some human writing gets a false flag. Nobody had a language model in 1776, and the Declaration of Independence still scored 98.4. We did not test why, so we will not guess. Researchers behind a study of GPT detectors and non-native English writers found that detectors consistently misclassify non-native English writing as AI generated.
• Plain AI text can pass, and edited AI text moves the score. A neutral explainer from a large language model scored 14.4, and the blog paragraph fell from 100 to 32.4 after a first-person rewrite. Paraphrased text from rewriting tools is untested.
• It is built for English. Text that does not look like English gets a notice that the score is not reliable. Two Spanish samples scored 5.8 (human) and 100 (AI), as expected, but two texts are a sanity check, not language support.
• Short text is labeled low confidence. Under 300 characters the card says Low confidence: the text is short in place of a verdict. The number still prints: a 17-word AI sentence scored 100 in our tests, and 60 exclamation marks scored 99.7, a number that means nothing.
• Text only, one text at a time. There is no file upload, no sentence highlighting and no way to name the model behind a passage. This is not a plagiarism checker. It is not built for code, and we did not test human-written code.

The result card prints its own reminder: No AI detector is fully accurate. Treat this as a guide, not proof, and review the text yourself.

How This AI Text Detector Works

This is text classification, not a lookup: there is no web search and no database of known texts. A transformer neural network reads your text, and a sigmoid function squeezes its raw output into a range from 0 to 1, which we scale to 100 and round to one decimal.

The engine behind this AI generated text detector is a public, MIT licensed fine-tuned model that separates human English from AI English. It runs CPU inference on our own server, with no third-party AI service. Its authors started from Microsoft's DeBERTa-v3 large, a transformer model with 24 layers and a hidden size of 1,024 per its Hugging Face card.

A tokenizer cuts a paste into word pieces, and the model keeps the first 768, so our page splits a long paste into sections first. The model pads every input to that size, so a 60-character paste costs about the same CPU time as a 3,000-character one, and a long paste costs one pass per section.

Using an AI Content Detector Responsibly

A score from any AI writing detector is a prompt to look closer, never proof, and nobody should be accused on one number. For essays, student writing and other academic integrity questions, earlier drafts, a talk about the work and other writing by the same person are better evidence. In editorial review, content marketing, freelance writing and hiring, compare two or three passages and look for a pattern.

Publishers ask where Google stands. Google's guidance on AI-generated content, published by Google Search Central in February 2023, says appropriate use of AI is not against its guidelines, while using it mainly to manipulate search rankings breaks the spam policies. The weight falls on quality and usefulness.

If your own writing scores high, reread it for places to add specifics only you know or to vary the rhythm. We never tested why a text gets flagged, so treat this as editing advice only. For perplexity, burstiness and false positives, read how AI detectors work and when they fail.

Local rules: If a school, client or employer has a rule on generative AI, follow that rule. This tool offers a signal only, and nothing here is academic or legal advice.

Related Free Tools

Where to go after a check.

• AI Humanizer: rewrites text, with no promise about detector scores.
• AI Detector and Humanizer: scores, rewrites and rescores with this same detector.
• Image to Text Converter: pulls text out of a screenshot or scan.
• PDF to Word Converter: turns a PDF into editable text.
• Website SEO Score Checker: audits the page your text will live on.
• How to Make AI Writing Sound Human: covers hand-editing habits.
• all free AI tools: every tool in the category.