Plagiarism Checker Plus, where you already write
Check for plagiarism and AI writing, and cite your sources, without copying between tabs — in your browser, in Google Docs, from Google Drive, from your AI assistant or from your own code.
Pick where you want to check
Your text is only sent when you ask for a check.
Check and cite anywhere you write
A Check button in the text box you are writing in, a check bar for any text you highlight, results in a side panel, a free grammar check that fixes issues in place, and one-click APA, MLA, Chicago or Harvard citations for the page you are reading.
Check your document without leaving Docs
Check a whole document or a selection for plagiarism and AI writing, see matches highlighted right in your doc, leave out quotes and your reference list, and insert citations at your cursor. The same add-on also works in Google Sheets™ and Google Slides™, with a free grammar check that fixes issues in place.
Check a file straight from your Drive
In the web app, pick a Google Doc, Sheet or Slides file, or a PDF or Word file stored in Drive, or upload one from your computer. You see the text and word count before anything is checked. Google only gives us access to the files you pick.
- Google Drive™Docs, Sheets, Slides
- PDF.pdf
- Word.docx, .doc
- Text.txt, .rtf, .odt
- Office.pptx, .xlsx
- Web page.html
Check text from your AI assistant
Connect Plagiarism Checker Plus to Claude and other assistants that support remote MCP servers. Ask it to check a draft for plagiarism or AI writing, and the checks use the words on your account. A free account works.
You: Check this draft for plagiarism and AI writing.
check_plagiarism → similarity score and matched sources
detect_ai → AI likelihood for each sentenceAdd plagiarism and AI checks to your own app
Submit text from your own code and get a plagiarism score with matching sources and an AI score with per-sentence verdicts back as JSON. Included in every paid plan. Open-source client libraries for JavaScript, Python, PHP, Ruby, Go, Java and .NET are on GitHub.
POST /api/public/v1/scans
{
"text": "The text you want to check…",
"tools": ["plagiarism", "ai_detect"]
}
202 Accepted
{ "id": "3f6c1e2a-…", "status": "processing" }Prefer the browser? Use the web app.
Paste or upload your text at app.plagiarismcheckerplus.com, or read the Help Center for step-by-step guides. Developers can start from the client libraries on GitHub.