Plagiarism Checker — Compare Texts Free
Compare two texts side by side and get a similarity percentage. Highlights matching sentences. Free, private — runs in your browser.
This tool compares two texts you provide. It does not search the internet or check against any database.
Plagiarism Checker — Detect Duplicate Content
Check your text for potential plagiarism and duplicate content. Paste your content and analyze it for phrases that appear elsewhere on the web. Useful for academic writing, blog posts, and SEO content that needs to be original.
The checker breaks your text into meaningful phrases and searches for exact and near-matches across the web. It highlights potentially duplicated passages and provides source URLs so you can verify whether the similarity is coincidental or problematic.
Original content is fundamental to both academic integrity and SEO performance. Search engines penalize pages with duplicate content by ranking them lower or excluding them from results entirely. For students and researchers, unintentional plagiarism from poor paraphrasing is a serious academic risk.
For SEO-focused content analysis, combine this tool with our Keyword Density Analyzer to ensure your original content is also well-optimized. Our Readability Checker helps verify that rewritten passages maintain clear, accessible language.
For a complete content quality pipeline, check originality with this tool, analyze readability with our Readability Checker, optimize keyword usage with our Keyword Density Analyzer, and verify that AI-generated content passes detection with our AI Content Detector.
How the Plagiarism Checker Works
- Paste your text into the input area or upload a text document
- Click Check — the tool breaks your text into meaningful phrases
- Each phrase is searched against web content for exact and near matches
- Potentially duplicated passages are highlighted with source URLs
- Review the overall originality score and investigate flagged passages
Understanding Plagiarism and Originality
Plagiarism is presenting someone else's words or ideas as your own. It ranges from direct copying (most obvious) to improper paraphrasing (restating ideas too closely) to missing attribution (using ideas without crediting the source). In academic contexts, plagiarism can result in failing grades or expulsion. In content marketing, duplicate content harms SEO rankings. Original writing can still coincidentally match existing phrases — common expressions, technical terminology, and widely-known facts are expected to overlap. Focus on passages that match unique phrasing from specific sources.
When to Check for Plagiarism
Check for plagiarism before submitting academic papers or theses, before publishing blog posts or marketing content, when reviewing content from freelance writers or agencies, after paraphrasing source material to verify sufficient originality, and when repurposing old content to ensure it is distinct from the original version.
Common Use Cases
- •Verify academic papers are original before submission to journals or universities
- •Review SEO content from freelancers to ensure it is not copied from competitors
- •Check marketing copy for unintentional similarity to competitor messaging
- •Analyze content readability alongside originality with our Readability Checker Readability Checker — Flesch Score & More
- •Ensure translated content is not a direct copy of source language pages
Expert Tips
- ✱Focus on unique phrase matches rather than the overall percentage — common expressions will always match
- ✱Check flagged passages in context — a properly cited quote is not plagiarism
- ✱For academic writing, run the check before submission, not after — early detection allows time to revise
- ✱Paraphrasing requires changing both the words and the sentence structure — simply swapping synonyms is not sufficient
Frequently Asked Questions
- There is no universal threshold. Academic papers should aim for under 10-15% similarity, excluding properly cited quotes. Marketing and SEO content should be under 5% to avoid duplicate content penalties. Technical documentation may have higher similarity due to standardized terminology. Context matters more than the raw number.
- This tool checks for text that matches existing web content, not whether text was generated by AI. AI-generated text is original in the sense that it doesn't copy specific sources, but it may lack depth or accuracy. For AI detection specifically, use our AI Content Detector tool.
- No. Properly attributed quotes — with quotation marks and a citation — are not plagiarism. The plagiarism checker may flag quoted passages as matching external sources, which is expected. Review flagged text in context to determine if it is properly attributed.
What plagiarism percentage is acceptable?▾
Can this detect AI-generated content?▾
Does quoting sources count as plagiarism?▾
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