Free Plagiarism Checker

Paste two texts and get an instant similarity score powered by Jaccard and Cosine similarity algorithms. Perfect for teachers comparing submissions, editors checking drafts against sources, and writers verifying their paraphrasing actually changed enough.

How it works (honestly)

Let's be clear about what this tool does and doesn't do: it compares two documents you provide — it does not scan the internet like Turnitin or Copyscape. You paste Document A and Document B; the tool tokenizes both, then computes overlap with two complementary algorithms. Jaccard similarity catches shared vocabulary; Cosine similarity catches shared phrasing patterns. Together they surface copying that simple word-matching misses.

Reading the score

Under 15% — normal (common phrases, quotes). 15–30% — review the highlighted passages. Above 30% — substantial overlap; rewrite and cite. For academic work, pair this with our AI content detector — AI-paraphrased plagiarism is the fastest-growing integrity problem in classrooms.

Frequently asked questions

Does this check against the internet?
No — it compares two texts you provide against each other.

What similarity percentage is acceptable?
Under 15% is fine; above 30% usually needs rewriting.

Is my text sent to a server?
No — comparison runs entirely in your browser.

Last updated: October 2026. Also try our AI content detector, text summarizer, and word counter.