Free online plagiarism checker with AI detection. Check text for duplicate content, get an originality score, detect AI-generated writing with perplexity and burstiness analysis, and see highlighted n-gram matches. No signup required. 100% browser-based — your text never leaves your device.
100% browser-based — your data never leaves your device
Check text for plagiarism, duplicate content, and AI-generated writing. Get an originality score with highlighted matches and AI detection analysis. 100% browser-based — your text never leaves your device.
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Copy your content and paste it into the text area, or upload a .txt file. The tool accepts up to 50,000 characters.
Click Check Plagiarism. The tool analyzes your text for internal repetition, n-gram overlaps, and AI-generation patterns.
See your originality percentage, highlighted duplicate sections, AI likelihood score, and a detailed breakdown of repeated phrases and suspicious patterns.
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Plagiarism CheckerCheck text for plagiarism, duplicate content, and AI-generated writing. Get an originality score with highlighted matches and AI detection analysis. 100% browser-based — your text never leaves your device.
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Plagiarism Checker is a free online seo tool that check text for plagiarism, duplicate content, and ai-generated writing. get an originality score with highlighted matches and ai detection analysis. 100% browser-based — your text never leaves your device. It works entirely in your browser — no downloads, no installations, and no server uploads required. digital marketers, content strategists, web developers use Plagiarism Checker when they need a fast, privacy-respecting way to process seo data without installing additional software. It supports capabilities such as originality score, ai detection, duplicate highlighting. Additional features include detailed report. Common use cases include check blog posts and articles for unintentional duplicate content before publishing, detect ai-generated text in student submissions and freelance work, review internal documentation for consistency and avoid repetitive phrasing. All processing happens locally using modern browser APIs, which means your data never leaves your device. This makes Plagiarism Checker ideal for working with sensitive data, proprietary code, or any situation where privacy matters.
Plagiarism Checker is a free online seo tool that helps you check text for plagiarism, duplicate content, and ai-generated writing. get an originality score with highlighted matches and ai detection analysis. 100% browser-based — your text never leaves your device. Key capabilities include originality score, ai detection, duplicate highlighting. All processing is done locally in your browser — no data is uploaded, stored, or shared with any server. There are no sign-ups, no file size limits, and no hidden charges. It is commonly used to check blog posts and articles for unintentional duplicate content before publishing.
Copy your content and paste it into the text area, or upload a .txt file. The tool accepts up to 50,000 characters.
Click Check Plagiarism. The tool analyzes your text for internal repetition, n-gram overlaps, and AI-generation patterns.
See your originality percentage, highlighted duplicate sections, AI likelihood score, and a detailed breakdown of repeated phrases and suspicious patterns.
| Category | Details |
|---|---|
| Input Limits | Maximum page size: Browser memory bound |
| URL limit: Unlimited | |
| Supported Formats | HTML, XML (sitemaps), Plain text, URLs |
| Browser Engine |
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All operations run entirely in your browser using built-in SEO APIs. No server uploads, no data storage, and no third-party requests.
Plagiarism Checker is ideal when you need to check blog posts and articles for unintentional duplicate content before publishing without installing software or uploading data to a server. Since everything runs in your browser, there is no setup time and no risk of your data being stored on external servers. For for monitoring live search performance, consider using Google Search Console. For for comprehensive technical SEO crawls, Screaming Frog may be a better fit. Plagiarism Checker fills the gap between heavyweight desktop tools and insecure online services that require uploading your data.
No. Plagiarism Checker processes everything entirely in your browser using JavaScript. Nothing you type, paste, or upload is ever transmitted to any server. Your data never leaves your device.
This tool performs local analysis on your text — detecting internal repetition, n-gram overlaps, and AI-generation patterns. For web-wide plagiarism checking, the results are best used as a pre-check before submitting to services that search public databases. All processing happens client-side for complete privacy.
Our AI detector uses three statistical signals: perplexity (how predictable the text is — AI text tends to be more predictable), burstiness (variance in sentence length — AI text tends to be more uniform), and repetitive pattern analysis (frequency of n-gram reuse). These signals are combined into a confidence score.
Get a percentage-based originality rating from 0-100% with color-coded severity indicators for quick assessment.
Statistical analysis estimates the likelihood your text was AI-generated using perplexity, burstiness, and pattern analysis.
Repeated phrases, n-gram overlaps, and suspicious sections are highlighted inline with context and frequency counts.
View a complete breakdown: total words, sentence count, unique vs repeated phrases, top repeated n-grams, and AI probability score.
Plagiarism Checker is useful in a variety of scenarios across different workflows:
Check blog posts and articles for unintentional duplicate content before publishing
Detect AI-generated text in student submissions and freelance work
Review internal documentation for consistency and avoid repetitive phrasing
Pre-check content before submitting to commercial plagiarism databases
AI detection accuracy improves significantly with texts over 500 words. Shorter texts may show higher variance in confidence scores.
High keyword density can sometimes trigger false positives in n-gram analysis. Cross-reference with our Keyword Density tool for a complete picture.
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Generate XML sitemaps from a list of URLs with priority and frequency settings.
Heading Analyzer
Extract and analyze heading structure (H1-H6) from any HTML.
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Analyze keyword frequency and density in any text for SEO optimization.
Schema Generator
Generate JSON-LD schema markup for articles, products, FAQs, local business, and more.