Plagiarism Checker Plus is a free AI detector, AI checker and plagiarism checker for Google Docs™. Check your whole document – or just the part you select – for plagiarism and for writing produced by ChatGPT, Gemini, Claude and other AI tools. See the results in a sidebar and highlight matched and AI-likely passages right in your document. No copying and pasting into another website.

WHO IT IS FOR
• Students: check an essay or paper before you hand it in, and fix what is flagged.
• Teachers: check a student's document without leaving Google Docs™, and see the source of every match.
• Writers and editors: confirm that a draft is original before it is published.

HOW TO CHECK A GOOGLE DOC FOR AI AND PLAGIARISM
1. Open your document and choose Extensions › Plagiarism Checker Plus › Check this document.
2. Connect your free Plagiarism Checker Plus account (once).
3. Choose Whole document or Selection, tick Plagiarism, AI detection or both, and click Check.
4. Review your scores, click any match to jump to it, and highlight matches or AI sentences in the document.

WHAT YOU GET
• Plagiarism checker: a plagiarism score, matches grouped by source website with how many passages match and their share of the document, and the source text for each match with the matching words marked.
• AI detector (AI checker, ChatGPT detector): an AI content score, with flagged sentences grouped into passages and rated Highly likely, Likely or Possible.
• Highlights in your document: shade every match or AI-likely sentence with one checkbox. Clear removes only the add-on's highlights and restores any colour your text had before.
• Leave things out: exclude quoted text and your reference list from the check. Excluded text isn't sent, checked or counted toward your words.
• Citations in 14 styles: look up a web page, DOI or ISBN, fix any details, then insert the citation at your cursor or add it to your reference list (alphabetical, with a hanging indent, under a References, Works Cited or Bibliography heading – created if missing). Styles: APA 7, MLA 9, Chicago 17, Harvard, IEEE, Vancouver, AMA, Turabian, CSE, ACS, ASA, APSA, Oxford and ABNT.
• Stay up to date: if you edit the document after a whole-document check, the sidebar offers Re-check. Reopen the sidebar later and your last check for that document is still there.

PRIVACY AND PERMISSIONS
• The add-on can only see the document it is opened in. It cannot open your other documents, your Google Drive, your Gmail or your Google account profile.
• Text is sent to app.plagiarismcheckerplus.com only when you click Check, and only the part you chose to check.
• We never sell your text and never use it to train AI models. Our use of information from Google APIs follows the Google API Services User Data Policy, including the Limited Use requirements.
• Remove the add-on from Extensions › Add-ons › Manage add-ons, or revoke its access at myaccount.google.com/permissions.

A NOTE ON RESULTS
No detector is perfect. AI detection gives a likelihood, not proof: it can flag human writing, especially formal or formulaic text, and miss AI text that has been heavily edited. Plagiarism matches show you the source text so you can judge each one. Use results as a starting point for review, not a verdict.

FOR SCHOOLS AND TEAMS
A Google Workspace administrator can install the add-on for a whole school, department or team from the Marketplace, so it appears under Extensions for everyone. Each person still connects their own account.

PRICING
Free to install. Checking needs a free Plagiarism Checker Plus account, which includes a monthly word allowance; paid plans add more words. The sidebar shows the words a check will use and the words you have left before you check.

Also available: the Plagiarism Checker Plus Chrome™ extension, for checking text boxes and highlighted text anywhere on the web.

Watch the 40-second demo: https://www.youtube.com/watch?v=yWY5TQHtqPo

Google Docs™ and Chrome™ are trademarks of Google LLC. Plagiarism Checker Plus is not affiliated with or endorsed by Google.