Plagiarism Self-Check
Compare your current draft against your own saved drafts to catch accidentally reused phrasing — runs in your browser.
About the Plagiarism Self-Check
Plagiarism Self-Check is a privacy-first writing companion that compares the essay or article you are working on right now against your own previously saved drafts — never against the public web. It is built for students, bloggers and copywriters who recycle the same source notes across multiple submissions and want to avoid accidentally reusing a sentence they wrote last semester. The tool slices each draft into overlapping 5-word phrases (called shingles) and computes a Jaccard similarity score between your current text and every saved draft. The result is a transparent percentage per draft, plus inline highlighting that shows you exactly which phrases you have repeated. Drafts you save are stored only in this browser's localStorage — there is no upload, no API key, no signup, and no third-party plagiarism service involved. Wipe your library at any time with one click.
How to use
- Paste or type your current draft into the editor.
- Type a memorable name (e.g. "History essay v1") and click Save current draft to add it to your private local library.
- Edit your text, paste a new version, or load it from a different file — similarity percentages update on every keystroke.
- Read the highlighted current draft to see the exact phrases that overlap with your closest match.
- Use the Delete link to remove a draft you no longer need, or Wipe library to clear everything in one click.
Benefits & key features
- 100% private — drafts and shingles never leave your device, ideal for confidential coursework.
- Real-time comparison while you write — no submit button, no API key, no rate limit.
- Inline phrase-level highlighting shows the exact words you have repeated.
- Pairs with the Essay Structure Checker for a complete writing review workflow.
- Open algorithm — Jaccard similarity on 5-word shingles, easy to reason about.
Pro tip
This tool only checks against drafts you have saved, so it is not a substitute for a service like Turnitin if your institution requires one. Use it to spot self-repetition before you submit, then run a final check through the institutional tool if needed.