Free AI Content Detector
Check if your text was generated by AI. Get a detailed score report with confidence breakdown to understand your content.
How It Works
Paste Your Text
Copy and paste any text you want to analyze for AI-generated content.
Run Detection
Our detector analyzes your text against known AI writing patterns and models.
Review Your Report
Get a detailed score report with AI probability, class breakdown, and a shareable results card.
What You Get With Every Scan
Every analysis gives you a complete, transparent breakdown of your content.
A single confidence score showing the likelihood your content was AI-generated, calculated across your entire text.
Overall confidence score
How AI detection actually works
Detectors don't read your text the way a person does. They measure statistical fingerprints (patterns in word choice, sentence rhythm, and predictability) that machine writing tends to share.
Perplexity
How surprised the model is by your text
A language model reads your writing one token at a time and predicts what should come next. If your text is full of expected words, perplexity is low. That is the signature of machine output that always picks the safest next word. Human writers stray more, so they score higher.
Burstiness
The rhythm of your sentences
Humans bounce between short, declarative sentences and long, comma-laden ones, and we cut things off. LLMs optimize for fluency and settle into an even rhythm, with similar sentence shapes line after line. Low burstiness alone is suggestive, never conclusive.
Stylometric fingerprints
The small things every model leaves behind
Detectors profile function-word frequency, transition repetition, punctuation distribution, and which sentence shapes dominate. GPT, Claude, Gemini, and Llama each leave subtly different patterns, which is why a strong detector reports a most-likely source model alongside the overall score.
Watermarks & training echoes
Patterns from how the model was built
Some providers experiment with statistical watermarks, biases baked in at sampling time. Adoption is uneven and paraphrasing destroys them, so they are not yet reliable. Detectors also pick up echoes of training data, like phrases the model has seen thousands of times during pretraining.
Putting it together
No single signal is enough. A well-built detector runs your text through several models, each tuned for a different signal, and combines the results into one probability. The output is not a yes/no verdict but a confidence reading, which is why our report shows a sentence-level breakdown alongside the overall score: you see where the machine-like patterns concentrate, not just whether they exist.
Accuracy is highest on long, unedited AI text and falls off as the writing gets shorter, more paraphrased, or more mixed. That is an honest limit of the technology, not a quirk of our implementation, and it shapes how we recommend you read the score, which the next section gets into.
Why Writers Choose Our AI Detector
Built for accuracy, speed, and transparency. Every scan gives you a complete picture.
Multi-Model Detection
Detects content from ChatGPT, GPT-4, Claude, Gemini, and other leading AI models with a single scan.
Detailed Score Reports
Get a full breakdown of AI probability, human probability, and mixed content scoring with per-class confidence levels.
Instant Results
Scan thousands of words in under two seconds. No waiting, no queues. Results appear the moment you click.
Human Score Calculation
Our proprietary algorithm calculates exactly how human your text reads, going beyond simple binary classification.
Private and Secure
Your text is never stored or used for training. Every scan is processed in real time and discarded after analysis.
Free Scans Every Day
Start scanning immediately with no account required. Free users get daily scans to check their content.
Where AI detectors fall short
No detector on the market is 100% accurate. Any tool that claims otherwise is either over-fitting to a marketing benchmark or quietly ignoring the edge cases. Here is where every detector gets the answer wrong, and what we do about it.
When human text gets flagged
The hardest writing for any detector to classify is the kind that looks statistically "safe": academic abstracts, legal boilerplate, technical docs, news ledes, and a lot of fluent ESL writing. To a model, that pattern looks identical to machine generation. The result is skilled human writers, often the most skilled at their format, getting a higher AI score than they deserve.
We treat this as a known cost. The UI surfaces a probability rather than a verdict, calls out the sentences that drove the score, and never tells you the text "is AI", only how likely the patterns are.
When AI text slips through
Paraphrased, hand-edited, humanized, or stitched-together AI text loses the statistical signature detectors look for. Short snippets (under roughly 150 words) also fall below the threshold where scores become meaningful. Three sentences just don't carry enough signal.
We address this by running multiple detection models per scan and reporting confidence honestly. A 62% score with a wide uncertainty band is genuinely different from a 95% score with a tight one. The report shows which you are looking at.
New models reset the baseline
Every time a frontier model ships (GPT-5, Claude 4, the next Gemini), detection accuracy on that model dips briefly because the fingerprint shifts. The community retrains and accuracy recovers. This is the central rhythm of the field.
We retrain on a rolling cadence so the catalog of detectable models stays current. There will always be a brief window where the freshest model is hardest to catch, and we say so.
Evidence, not proof
A high score is a strong reason to look more carefully; a low score is a strong reason to trust your other signals. The middle is where you read the sentence-level view. Detectors work best as one input into a decision, not a single accusatory verdict. Used that way, the technology is genuinely useful.
What detectors catch, what slips through
A concrete look at the writing patterns that almost always trip a detector, and the ones that usually don't. Your text in the second column? Expect a lower score even if it was AI-generated.
High signal
Patterns detectors usually catch
Templated openings
"In today's fast-paced world…", "It is important to note that…", "In conclusion…". Phrases the model has produced thousands of times in training.
Uniform sentence rhythm
A paragraph where every sentence is roughly the same length and opens with a similar grammatical structure.
Excessive hedging
"Could," "may," "often," "tends to", repeated in places a confident human would just make a claim.
Listicle scaffolding
Three-bullet payoffs everywhere, perfectly parallel phrasing across items, conclusions that restate the intro without adding anything.
Tonal flatness
A consistent, evenly polite, faintly enthusiastic register that never breaks for a joke, a frustration, or a specific opinion.
"Delve" vocabulary
Words the major LLMs reach for more than native writers do: delve, tapestry, vibrant, realm, navigate, multifaceted.
Low signal
Patterns that usually slip through
Heavy paraphrasing
Once an AI draft has been rewritten line-by-line in a real writer's voice, the statistical signal is largely gone.
Short snippets
Under ~150 words there is not enough text for perplexity and burstiness to settle into a reliable signal.
Mixed AI + human writing
A human intro and conclusion bracketing an AI middle, or every-other-sentence edits. Either blends signatures and lowers the score.
Humanizer output
Text run through a dedicated humanizer (ours or anyone else's) is, by design, harder to flag.
Brand-new model output
The first few weeks after a major model launches, before detectors have retrained on its fingerprint.
Highly formulaic prose
Code, structured data, recipe steps, and citation-heavy paragraphs all have low natural burstiness, which makes the signal noisier in both directions.
A single high score on a short snippet is not a verdict; a single low score on a paraphrased draft is not an all-clear. Read the sentence-level view and your other signals alongside the headline number.
How to use the WriteHuman AI detector
Free to run, no account required for daily scans. Five steps from a blank box to a confident read.
- 1
Paste your text into the detector above
Drop in at least a few paragraphs. A couple hundred words is the sweet spot. Scores on shorter snippets carry less signal, so for a real read on a draft, scan something close to the full piece.
- 2
Click Run Detection and wait a few seconds
The text is sent through several detection models in parallel. Most scans finish in two to five seconds; longer documents take a bit more.
- 3
Read the overall AI probability score
A single percentage at the top of the report, showing how likely the text was AI-generated. Treat it as a probability, not a verdict. Above ~70% is a strong signal, below ~30% is a strong all-clear, and the middle is where you look closer.
- 4
Open the class breakdown and sentence-level view
The report shows the most-likely source model and highlights the specific sentences driving the score. This is where false positives become legible. If the flagged sentences are obviously yours, the headline number is probably misleading.
- 5
High score? Run it through the humanizer
Detected AI text can be rewritten in seconds with our humanizer, which is built to preserve meaning while restoring the natural rhythm and vocabulary range detectors look for. Re-scan to confirm.
Open the humanizer
Detect. Then Humanize. One Seamless Flow.
Found AI content? Fix it instantly. Our detector works hand-in-hand with the WriteHuman humanizer.
“The implementation of artificial intelligence in modern content creation has demonstrated significant potential for enhancing productivity and output quality.”
AI Detected: 89%“AI is changing how we create content, and the results so far are genuinely promising. It's reshaping the writing process in ways we didn't expect.”
Human: 4% AI- Detect AI content with a single click
- Humanize flagged text without leaving the page
- Re-scan to confirm your content reads naturally
Trusted by Writers and Professionals
See why thousands of users rely on the WriteHuman AI Detector every day.
“0 complaints, helps speed up work tremendously.”
Gavin Waymire
“Very useful, insightful, meaningful. The work is simplified due to technology.”
Deva Priya
“99% flawless. Still must proofread for fluff terms.”
kris stewart
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Frequently Asked Questions
Everything you need to know about AI content detection.