Plagiarism Checker Info
Learn about plagiarism, how to check content, and tools and techniques for ensuring originality.
Understanding Plagiarism Checking
A full plagiarism scan requires comparing text against billions of web pages and academic papers — this needs server-side processing. We recommend these trusted free tools:
- DupliChecker — Free online plagiarism checker
- SmallSEOTools — 1000 words free per check
- Quetext — DeepSearch technology
- Grammarly — Premium plagiarism checker
Self-Check: Unique Phrases
Search any phrase in Google to manually check if it appears elsewhere:
About Plagiarism Checking
Use the phrase search tool to manually check if specific sentences from your content appear elsewhere online. For full scans, use one of the recommended tools above.
About this calculator
Learn what plagiarism is and how to avoid it, and compare two pieces of text to see how similar they are.
This is not a web-wide plagiarism scanner. It compares only the two texts you paste, plus tips for checking online.
How to use it
- Paste Text 1 and Text 2.
- Press Check Similarity.
- Rewrite and cite any overlapping passages.
How similarity is scored
The tool measures overlap in words and phrases (for example, the share of matching word sequences) and reports a similarity percentage. Matching text is not automatically plagiarism: quoted passages with citations are fine, and common phrases will overlap. Professional checkers (Turnitin, Copyscape) compare against databases of web pages and papers. To avoid plagiarism: paraphrase properly, quote with attribution, and cite every source.
Worked example
Interpretation
| Under 10% | Usually fine |
| 10 to 25% | Check matching passages |
| Over 25% | Rewrite or quote and cite |
Tips and common mistakes
- Cite sources even when you paraphrase.
- Use quotation marks for exact words.
- Keep notes of where each idea came from.
- Rewrite structure, not just synonyms.
- Ask your institution which checker it uses.
Frequently asked questions
What is plagiarism?
Presenting someone else's work as your own.
Does 20% similarity mean plagiarism?
Not necessarily; it depends on what matches.
Does this compare against the internet?
No, only the two texts you paste.
How do I paraphrase properly?
Restate the idea in your own structure and cite it.
Are quotations plagiarism?
No, if marked and cited.
Is it free?
Yes.