Text Overlap Highlighter
Compare two texts and highlight word sequences they share, with the percentage of each text that overlaps. No web search – only the texts you paste.
Runs entirely in your browser. Your data is never uploaded.
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View AllWhat is Text Overlap Highlighter?
Finds passages that two texts have in common and highlights them in both. It reports what percentage of each text is covered by shared passages and lists every shared passage. It only compares the two texts you paste – it does not search the internet or any database, so it cannot detect copying from other sources.
How to use Text Overlap Highlighter
- Paste the source text into Text A and the text to check into Text B.
- Choose the Minimum shared passage length in words (5 by default).
- Read the overlap percentages and see the highlighted passages in both texts.
- Review the list of shared passages.
Example
A: The quick brown fox jumps over the lazy dog near the river. B: Yesterday the quick brown fox jumps over a sleeping cat.
60% of text B found in text A · 1 shared passage: "the quick brown fox jumps over" (6 words)
When to use Text Overlap Highlighter
Use it to check a student answer against a known source, compare a rewrite with the original, or find reused paragraphs between two documents. Shorter minimum lengths find more matches but also common phrases ("at the same time"); paraphrased or translated text is not detected. It is a comparison aid, not proof of plagiarism.
How Text Overlap Highlighter works
Both texts are split into words (Unicode letters and digits), lower-cased and stripped of accents for matching. Every sequence of N consecutive words (N = minimum passage length) in Text A is indexed. The tool then walks through Text B; wherever an N-word sequence also exists in A, it extends the match as far as both texts continue identically and records that passage. Words inside matches are highlighted in both texts. Overlap = matched words ÷ total words of that text × 100.
Common Use Cases
- Checking an essay against a specific source text
- Verifying that a rewritten article is sufficiently different from the original
- Finding passages copied between two contracts or reports
- Comparing two translations or drafts for reused sentences
Security Note
Both texts are processed locally in your browser and are never uploaded.
FAQs
Does it search the internet for plagiarism?
No. It only compares Text A with Text B. To check against the web you need a service with a large index of documents.
Are differences in case or accents ignored?
Yes. Words are compared in lower case and without diacritics, and punctuation between words is ignored.
What minimum passage length should I use?
5–8 words is a good balance. 3–4 words catches many common expressions; 10 words only finds clearly copied sentences.