Text Similarity Checker — Compare Two Texts, Find Real Overlap

Word-level trigram overlap + longest common sequence between two texts — computed in your browser in milliseconds. Perfect for teachers, editors and authors.

Quick answer: Compare two texts side by side and get an honest overlap percentage with the longest common phrases highlighted. 100% local — nothing is uploaded. Free, instant.

How to use

Paste text A on the left, text B on the right.
The overlap %, matched-word count and longest common phrases appear instantly.
Use the phrase list to decide: coincidence, lazy paraphrase, or citation needed.

About this tool

This is the tool teachers and editors actually need: paste two versions — a student submission and a reference answer, your draft and a source you must not copy, two candidate intros — and get a precise overlap score plus the longest common word sequences listed verbatim. It is the same shingle-matching arithmetic search engines use for duplicate detection, running entirely on your device. Nothing is uploaded, nothing is stored.

FAQ

What counts as a good/bad similarity score?

There is no universal threshold: identical boilerplate can be innocent, 10% copied argumentation can be fatal. Read the highlighted common phrases and judge the meaning, not just the number.

How is the percentage computed?

Three-word trigram containment: shared trigrams divided by the smaller text's trigram count, plus a longest-common-sequence listing. Same family of arithmetic search engines use for near-duplicate detection.

Is either text uploaded?

No — comparison runs 100% in your browser. Nothing leaves the page.

Can it compare translations?

No — it compares word overlap, so translations will score low. It is for same-language comparison.

Teacher use-case: is it fair to students?

It shows exactly which phrases overlap so you can have an evidence-based conversation instead of accusing on a raw number.

Is it free on mobile?

Yes — instant, free, no app install.

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Text Similarity Checker — Compare Two Texts, Find Real Overlap

How to use

About this tool

FAQ

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