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Compare two documents and measure how closely their content overlaps.
Text Similarity Checker: Paste two text passages to instantly see their similarity score as a percentage. The tool uses cosine similarity, Jaccard index, and other algorithms. Useful for plagiarism checks, content deduplication, and SEO cannibalization analysis.
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Text Similarity Checker — A Text Similarity Checker is a free tool that compares two text passages and calculates their similarity percentage using multiple algorithms.
Paste the first text in Text A and the second in Text B.
Run comparison to generate similarity score and fingerprints.
Review percentage and Hamming distance to gauge overlap.
Edit and re-check if you need stronger differentiation.
Detecting near-duplicate pages in SEO workflows
Comparing article revisions during editorial QA
Checking overlap between landing pages targeting similar terms
Reviewing adapted content before republishing
Detecting how similar two pieces of text are sounds simple but has surprising depth. The naive approach — counting exact word matches — misses paraphrasing, synonyms, and reordering. Real similarity algorithms use mathematical techniques that measure semantic overlap, structural similarity, or both. This tool uses a combination of approaches to give you a defensible similarity score for SEO, content QA, and plagiarism detection workflows.
| Algorithm | What it measures | Best for |
|---|---|---|
| Cosine similarity | Angle between word-frequency vectors | Topical similarity, ignoring length |
| Jaccard index | |intersection| / |union| of word sets | Set-based overlap (vocabulary overlap) |
| Levenshtein | Edit distance (insertions / deletions / substitutions) | Detecting typos, near-identical strings |
| SimHash | Locality-sensitive hash; Hamming distance | Near-duplicate detection at scale |
| N-gram overlap (shingling) | Overlap of consecutive word sequences | Plagiarism detection (catches verbatim copying) |
| Semantic embeddings (BERT etc.) | Neural network vector distance | Detecting paraphrasing / synonyms |
Cannibalization happens when two of your own pages target the same query and compete for rankings. Both rank lower than one combined page would. Symptoms:
Fix: compare the two pages with this tool. If similarity >50%, consolidate by (1) merging the better-performing content into one page, (2) 301-redirecting the lesser page to the merged page, (3) updating internal links. If similarity is genuinely low but they target the same query, differentiate the content (one informational, one transactional).
High similarity isn't automatically a problem — context matters. Use the score plus a manual review to make decisions.
All comparison runs in your browser. Neither text is sent to any server. Safe for proprietary content, confidential documents, or student work where privacy is important.
When updating an existing article, compare old and new drafts to ensure meaningful change rather than superficial edits.
For clusters targeting related terms, compare page introductions and key sections to avoid repeating near-identical phrasing across URLs.