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.

Text A0 words

Text B0 words

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

01Paste your text into the input area or upload a text document
02Click Check - the tool breaks your text into meaningful phrases
03Each phrase is searched against web content for exact and near matches
04Potentially duplicated passages are highlighted with source URLs
05Review 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

What plagiarism percentage is acceptable?→

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.

Can this detect AI-generated content?→

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.

Does quoting sources count as plagiarism?→

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.

Related tools

12 suggested