Free AI Detector

Wondering if a piece of writing was made by a human or an AI? Paste it in and find out in seconds. Our AI checker scans for patterns left behind by ChatGPT, Claude, Gemini, and Llama — and shows you exactly which sentences look AI-generated, not just a vague score.

Every major model
Sentence-level
Multi-language
PlagiarismAI detector
0 / 1,000 words·0 chars

Every major AI model

Trained on output from ChatGPT, Claude, Gemini, Copilot, Llama, and Mistral — updated as new models ship, so coverage keeps pace with the tools people actually use.

Sentence-level confidence

Not a vague single number. Every sentence is scored and color-coded with a confidence rating, so you know exactly which passages to act on and which to verify.

Private by design

Your text is processed in real time and never shared or used to train AI. Free scans are not retained. Your writing stays yours.

What Our AI Detector Analyzes

AI text reads the way it does for measurable reasons. Click a signal to explore it — or let them cycle.

Perplexity — the predictability of language

28
Perplexity
Too smooth
Likely AI

AI models pick the most statistically probable next word, producing writing that is unusually smooth — low perplexity. We measure it across your text and flag passages too predictable to be natural.

Low-perplexity flagsWord-probabilityStatistical smoothness
Plus everything a serious workflow needs

Sentence-level highlighting

Every sentence scored and color-coded green, amber, or red — so the AI signal shows up exactly where it is.

High accuracy, low false positives

Thresholds are calibrated to avoid flagging genuinely human writing, because a false accusation has real consequences.

Combined AI + plagiarism

Run both checks in a single scan and get one unified originality report instead of juggling two tools.

Bulk document scanning

Upload a full class set or a batch of articles and get an individual report for each, stored in your folder.

API access for teams

Integrate detection into your LMS, CMS, or review workflow — submissions scanned the moment they upload.

Private by design

Documents are processed in real time and never shared or used to train AI. Your content stays yours.

Inside Your AI Detection Report

plagiarismcheckerplus.com/ai/draft-04
Export PDF
52%
Overall AI signal
Likely mixed authorship
3 of 6 sentences flagged · 2 high-confidence
Closest model match
GPT-4 / GPT-4o
83% pattern match
HumanAI-generated
Sentence-by-sentence breakdown
HumanLikely AIAI (high)
s1
Climate migration has emerged as one of the defining challenges of our century.
low
12%
s2
Moreover, the multifaceted nature of this issue necessitates a comprehensive approach.
high
94%
s3
Researchers in Bangladesh have tracked displacement patterns since 2003.
low
18%
s4
It is important to consider that policy frameworks must evolve to meet these unprecedented demands.
high
89%
s5
Most affected families return within two years if work returns first.
low
8%
s6
Furthermore, stakeholders must collaborate effectively to navigate complex dynamics.
high
91%
Perplexity
Low (28)
Burstiness
0.18
Repetition score
Medium

Overall AI score at a glance

A single percentage shows how much of your text looks AI-generated. Color-coded so you know in one second whether to publish or rewrite.

Sentence-level AI highlights

Every flagged sentence is color-coded by AI confidence. Click any sentence to see why it was flagged: predictable phrasing, statistical patterns, structural tells.

Confidence rating per flag

We do not just say AI or human. You get a confidence rating: high, medium, or low. This matters because no AI detector is 100% accurate. Confidence ratings tell you which flags to take seriously and which to double-check.

Edit and rescan in one click

Fix flagged sentences in the same window, then rescan. No copy-pasting. No losing your work.

Downloadable PDF report

Export a clean report for a professor, editor, or client. Use it as proof when you need it.

Why You Need an AI Detector

A year ago, you could spot ChatGPT writing at a glance. Now it sounds like a human. Editors, teachers, and recruiters are getting work submitted that may or may not be original, and asking the obvious question: is this AI? Guessing is no longer safe. Checking is fast.

01

AI-generated text is everywhere now

Freelancers use ChatGPT to draft articles. Students use Claude on take-home essays. Job applicants use AI to write cover letters. Most of the time, you have no way to tell. An AI detector gives you a number to work with.
02

Google penalizes sites for scaled content abuse

Google's helpful-content systems flag pages built from low-effort AI text. Your site can lose traffic overnight if too much of it looks machine-written. Run drafts through the AI checker before you publish to keep your domain safe — see Google's scaled content abuse policy for the specifics.
03

Schools and clients want proof your work is yours

You may have written every word yourself, but if your professor or client uses an AI detector and it flags your work, you need a defense. Run your own scan first. If it comes back clean, you have proof. If it comes back high, you can rewrite the flagged sections.
04

A standard plagiarism check will not catch AI

AI text is technically original because it was never published anywhere. A normal plagiarism checker will say it is clean. An AI detector is built for exactly this gap. Run both for a full check, or use our plagiarism checker for the other half.

What Our AI Detector Spots

AI writing is not one thing. Different models leave different fingerprints. The detector is trained on output from the major language models so it can flag them all in one pass.

G

ChatGPT (GPT-4o, GPT-5)

The most common source of AI text on the internet. We track patterns from every public GPT release, including the latest models.

C

Claude (Anthropic)

Claude has a different writing style than ChatGPT: calmer, more hedged, more nuanced. The detector is tuned to recognize Claude output specifically, not just generic AI.

✦

Gemini (Google)

Gemini text has its own structural tells — particular cadence, phrasing patterns, and hedging vocabulary. We score for them.

L

Llama, Mistral & open-source

Open-source models are popular with developers building wrappers and content farms. They are also harder to detect because output varies more. Our detector covers them too.

½

Mixed & lightly edited AI

A common pattern: someone writes a rough draft with AI, then edits it. The detector flags partial AI even when a human has cleaned it up. Each sentence is scored on its own.

~

Humanized AI (paraphrased to dodge)

Humanizer tools rewrite AI text to sound less robotic. We catch the patterns they leave behind. Both the original AI structure and the humanizer's reshuffling show up in the scan.

Built for the Way You Work

Teachers & academics

You read 50 essays a week and you cannot fact-check every one for AI. Run them through the AI detector first. The ones that come back clean go on top of your pile.

Editors & publishers

You commission articles from writers you trust, but you still need to verify. One scan tells you whether a draft is hand-written or AI-generated. Catch it before it ships, not after.

SEO & content teams

You produce content at scale. Google has gotten aggressive about AI text on sites. Run every piece through the AI detector before it goes into your CMS.

Students & writers

You wrote the thing yourself, but your professor or client might run it through their own AI detector. Run yours first. If it flags any sentences, you can tighten them before submission.

Recruiters & hiring managers

You read hundreds of cover letters. AI-written ones are getting harder to spot at a glance. A 30-second AI check on shortlisted candidates tells you who actually wrote what they sent you.

AI Detection at Scale

Universities, publishing houses, and large content operations need infrastructure to match the volume. Our institutional tier is built for it.

Admin dashboard & user management

Manage users, monitor usage, review flagged documents, and export reports from one control panel — no technical setup required.

Internal database cross-referencing

Combine AI detection with institutional plagiarism checking against your own uploaded private library of past submissions and research.

LMS integration via API

Connect to Moodle, Canvas, Blackboard, or any LMS. Submissions are scanned at the point of upload, with results delivered to instructors automatically.

Compliance-grade privacy

No retention beyond the analysis session. For institutions under FERPA, GDPR, or similar regimes, this is not optional — and we do not treat it as one.

Bulk processing

Handle high volumes without degrading in speed or accuracy — 500 end-of-term submissions or a quarterly content audit.

Department-level oversight

Coordinators and department heads control access, monitor usage, and review reports across courses and teams.

Detection is the first step to an honest conversation.

AI detection does not replace human judgment, and it should never be the sole basis for an academic-integrity decision. What it does is identify content that warrants a closer look — and give that judgment something to stand on.

How Do AI Detectors Work?

Detectors reverse the logic of AI generation: if models produce the most probable next word, then highly probable text is a signal of machine authorship.

Token probability

AI text leans on statistically expected vocabulary. Human writing is messier and more idiosyncratic.

Sentence-length variance

Humans vary their rhythm naturally. AI writing tends to be more metrically uniform.

Semantic coherence

AI writing is locally coherent but globally template-like. Detectors look for that predictable macro-structure.

Stylistic consistency

Human writing has voice shifts and quirks. Single-prompt AI output is stylistically flat in ways classifiers catch.

None of these signals is reliable alone. The most accurate systems use ensemble models — multiple classifiers weighing signals against each other — to return a calibrated probability, not a binary verdict.

Check for AI Wherever You Work

No installation, no setup. Run a check right in your browser, add the extension to check as you browse, or wire detection straight into your own stack.

Web app — no install

Use the full AI detector in any browser, on any device. Paste your text and scan in seconds.

Open the web checker

Chrome extension

Select any text on any web page and run an AI check in one click, without switching tabs.

Request early access

API for teams

Plug the AI detector into your CMS, LMS, or QA workflow and scan submissions automatically.

Request API access

Frequently Asked Questions

Yes. You get one free AI detection scan (up to 1,000 words) with no account and no card on file. The free check gives you a full AI score, sentence-level highlights, and confidence ratings. Create a free account for 3,000 words every month, or upgrade if you need longer documents, unlimited scans, or a downloadable PDF report.

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