How to Check for Plagiarism in Google Docs
Updated
To check for plagiarism in Google Docs™, install the Plagiarism Checker Plus add-on, open your document and choose Extensions › Plagiarism Checker Plus › Check this document. Tick Plagiarism, click Check document, and the sidebar lists the matching sources with the share of your document each one covers. Click any match to jump to it in the doc.
Google Docs doesn’t include a plagiarism checker of its own (see Does Google Docs have a plagiarism checker?), so you add one. The add-on checks the document you have open — and only that document — against web sources.
Check a Google Doc for plagiarism
- Open your document in Google Docs.
- Choose Extensions › Plagiarism Checker Plus › Check this document.
- Sign in if asked. A free account is required; you can create one on the sign-in page.
- Pick Whole document, or select some text and pick Selection.
- Under Look for, tick Plagiarism. You can tick AI-generated text too.
- Optional: under Exclude, tick Quoted text and/or Reference list so properly quoted passages and your bibliography aren’t counted.
- Check the word count shown in the sidebar, then click Check document. Plagiarism checks can take a few minutes on long documents; you can keep working meanwhile.
- Review the Plagiarism tab: the overall score, then each source with how many matches it has and how much of your document it covers.
Working through the matches
Matches are grouped by source website. Click a row to select that passage in your document, or switch to seeing the matches in the order they appear in your text. Open source opens the matching page so you can compare the wording.
For each match, decide what it is:
- A quotation you forgot to mark. Add quotation marks and a citation.
- A paraphrase that stayed too close to the original. Rewrite it in your own words and structure, and still cite the source.
- A source you used but didn’t cite. Add the citation. The Cite button next to a match starts a citation for that source — see How to add citations in Google Docs.
- A common phrase or technical term. Short, generic matches are normal and usually need no change.
To see every match at once, tick Highlight matches in document; matched text gets a pale red background. Clearing highlights restores your original formatting.
Quotes and references inflate the score
Correctly quoted and cited text still matches its source — that’s expected, not plagiarism. If your paper quotes a lot or has a long reference list, use the Exclude options so the score reflects your own writing. Excluded text isn’t sent, checked or charged. Details in Leave out quotes and your reference list.
After you revise
When you edit the document after a whole-document check, the sidebar shows Document edited since last check with a Re-check button. Run it once you’ve fixed the matches to confirm the result.