The short answer
Google Docs has no built-in plagiarism checker. To check a Doc, use one of three ways: run an originality report in Google Classroom if your teacher turned it on, install a plagiarism checker add-on from the Extensions menu, or copy the text into a web plagiarism checker.
- Google’s originality reports work only with a Google Workspace for Education account, inside Classroom or Assignments.
- An add-on works in any Google Doc and keeps you in the document.
- Copy and paste needs nothing installed.
The three ways compared
| Way | Who can use it | Where it runs | Limit to know |
|---|---|---|---|
| Google’s originality reports | Students and teachers with a Google Workspace for Education account, on assignments where the teacher turned reports on | Google Classroom, or Assignments inside a school learning system | Up to 3 reports per student before turning in |
| Plagiarism Checker Plus add-on | Anyone with a Google account and a free Plagiarism Checker Plus account | A sidebar inside Google Docs | A free account has a monthly word allowance |
| Copy and paste into the web checker | Anyone | A browser tab | First check free up to 1,000 words without sign-up |
1. Google’s originality reports (Classroom and Assignments)
Google’s own plagiarism feature is called originality reports. It is not a button in Google Docs. It lives in Google Classroom, and in Assignments for schools that use another learning system.
Who can use it
Google’s Classroom Help page Turn on originality reports says originality reports are only available for Google Workspace for Education accounts. So a personal Google account does not have them. A teacher also has to turn reports on for the assignment.
What it checks
The same page says a report compares a student’s Google Docs, Google Slides and Microsoft Word files against webpages and books on the internet. It links to detected sources and flags uncited text. If the school’s administrator has enabled school matches, it can also check against previous student submissions from the school or district.
Steps for students
These are the steps on Google’s help page Run an originality report on your work:
- On a computer, go to classroom.google.com.
- Click the class, then Classwork.
- Click the assignment, then View instructions.
- Under Your work, upload or create your file.
- Next to Originality reports, click Run.
- Under the file name, click View originality report.
If you do not see Originality reports on the assignment, your teacher has not turned them on for it.
Limits, as Google documents them
- Three runs per student. You can run up to 3 reports on your work before you turn it in.
- Your runs are private. Google’s student page says your teacher cannot find the reports that you run. After you turn in your work, Classroom automatically runs a report that only your teacher can find.
- Five assignments per class on the free edition. With a Google Workspace for Education Fundamentals account, a teacher can turn on originality reports for 5 assignments per class. Google says unlimited reports need the Teaching and Learning upgrade or Google Workspace for Education Plus.
- File size. A document must not exceed 2MB for a report to be created.
If your school uses Canvas, Schoology or Moodle
Google describes Assignments as an add-on application for learning management systems, and lists Instructure Canvas, PowerSchool Schoology Learning and Moodle. Its help page on originality reports in Assignments gives the same kind of limits: Education accounts only, 5 assignments per course with Education Fundamentals, and 3 reports per student before submitting.
For what these reports do and do not show about AI writing, see can Google Classroom detect AI?
2. A plagiarism checker add-on inside Google Docs
An add-on puts a checker in a sidebar next to your writing. It works with any Google account, and you do not need a teacher to turn anything on. The steps below are for the Plagiarism Checker Plus Google Docs add-on, which is free to install.
- Install the add-on. Open the add-on page and click Install from Google Workspace Marketplace. Google asks you to allow three permissions. The add-on page explains each one.
- Open the sidebar. In your document, choose Extensions › Plagiarism Checker Plus › Check this document.
- Connect your account. Sign in once with your free Plagiarism Checker Plus account. The website opens in a small window to confirm.
- Choose what to check. Pick Whole document or Selection, and tick Plagiarism. You can leave quoted text and your reference list out of the check. The sidebar shows the words a check will use before you start.
- Click Check. You see the share of the document that matches other sources, the matches grouped by source website, and the source text for each match.
- Review and highlight. Tick Highlight matches in document to shade every match. Click any match to jump to it in your document. Open source visits the page, and Cite builds a citation.
Things to know before you start:
- It needs a free account. There are no guest checks in the add-on. A free account includes a monthly word allowance.
- It reads only the open document. The add-on asks for permission to view and manage the document it is opened in. It cannot see your other documents, your Google Drive or your Gmail.
- Text is sent only when you click Check. Only the part you chose is sent, minus anything you excluded.
- It works in Google Docs only, not in Slides or Sheets.
- It can re-check. If you change the document, the sidebar offers Re-check.
If you write in other places on the web, there is also a Chrome extension.
3. Copy and paste into a web plagiarism checker
This way needs nothing installed. It suits a single check or a short text.
- Open your Google Doc. Make sure your quotations, citations and reference list are in place.
- Select the text. Press Ctrl+A on Windows or Cmd+A on a Mac to select everything, or drag to select one section.
- Copy it. Press Ctrl+C or Cmd+C.
- Paste it into the checker. Open the Plagiarism Checker Plus checker, click in the text box and press Ctrl+V or Cmd+V.
- Run the check and open the report. The report links every matching passage to its source.
- Fix the text in your Doc, not in the checker, so your document stays the one true copy.
The first check is free up to 1,000 words without sign-up. If your document is longer, check it a section at a time or use the add-on.
What to do with the results
Whichever way you use, the result is a list of passages that match other sources. A match is not the same as plagiarism. Read each one and decide what it needs:
- Exact words from a source: add quotation marks and a citation.
- An idea from a source in your own words: add a citation.
- A quotation that is already cited, or common wording: leave it.
If you need to build a reference, the citation generator can help. For more on reading results:
- How to check for plagiarism covers the full method and what to do with each kind of match.
- How to interpret a plagiarism report explains what the score can and cannot tell you.
- How much plagiarism is allowed? explains why there is no safe percentage.
- The types of plagiarism and our plagiarism examples show what the problems look like. See also is paraphrasing plagiarism?
Which way to use
- Your teacher turned on originality reports: use them. It is the same feature that produces your teacher’s report. You have 3 runs, so finish the draft first.
- You have a personal Google account, or no report on the assignment: use an add-on to check without leaving the document.
- You want one quick check of a short text: copy and paste it into the web checker.
If your course has rules about which tools you may use on your work, follow them. Formatting the same paper? See how to set up MLA format in Google Docs.