Plagiarism Self-Checker

No, and we're honest about it. Our tool performs local, document-based similarity detection. It compares texts you provide against each other or against your personal reference corpus. True internet-wide plagiarism checking requires API access to massive databases, which is impossible without server-side processing. This tool is perfect for comparing assignments, detecting self-plagiarism, and educational purposes.

Our tool uses advanced statistical similarity algorithms that run entirely in your browser: N-gram Generation (creating word chunks for comparison), Jaccard Similarity (measuring overlap between word sets), Cosine Similarity (vector-based text comparison), and Longest Common Subsequence (LCS) for detecting structural similarity. These are the same mathematical foundations used by academic plagiarism tools.

Our plagiarism checker can detect: Exact Plagiarism (copy-paste duplication), Mosaic Plagiarism (mixing copied phrases with original content), Paraphrasing (rewording but keeping structure), Self-Plagiarism (reusing your own previous work), and Redundant Content (internal repetition within a document). Each type is color-coded in the results for easy identification.

100% Private. All analysis happens locally in your browser using JavaScript. Your essays, articles, and documents are never uploaded to any server. This makes our tool completely safe for analyzing confidential academic papers, business documents, or any sensitive content. Your text remains on your device at all times.

This is not an AI detector—it identifies writing patterns often associated with AI-generated content: Sentence Length Uniformity (AI tends to write same-length sentences), Low Lexical Diversity (repetitive vocabulary), and Repetitive Patterns (similar phrase structures). It serves as a style warning, not a definitive AI detection verdict.

For academic and professional writing, aim for 85% or higher originality. Similarity below 15% is generally acceptable (Low Risk). Between 15-40% requires review (Medium Risk). Above 40% similarity indicates significant matching content that should be rewritten or properly cited (High Risk). Note that properly quoted and cited text is expected to show similarity.

Yes! Use the Corpus Check mode. You can add multiple reference documents to your personal corpus, then check any new text against all of them simultaneously. This is ideal for teachers checking student submissions against previous work, or writers ensuring they don't repeat content across articles.

Our File Upload mode supports TXT files for direct text extraction. For best results with DOCX and PDF files, we recommend copying the text content and using the paste feature in Compare or Single Text modes. This ensures accurate text analysis regardless of document formatting.

Matching text is color-coded by severity: 🔴 Red (High) = 40%+ similarity per sentence (likely copied), 🟠 Orange (Medium) = 15-40% similarity (possibly paraphrased), 🟢 Green (Low) = below threshold (minimal similarity). You can adjust the sensitivity threshold in the Analysis Settings panel.

Yes! Once the page is loaded, you can disconnect from the internet and the tool will continue to function perfectly. All plagiarism detection algorithms run locally in your browser using JavaScript—no server connection required after initial page load.