What the two editors do on their own
Neither company publishes a sentence saying “there is no AI detector here”, so this section rests on what their documentation does describe. We found nothing in either that reads a document and estimates whether a model wrote it.
Word has one checking feature people mistake for detection. In Word for Microsoft 365, Editor > Similarity compares your document with text on the web and, in Microsoft’s own description, shows how much of your content matches as a percentage along with the number of distinct passages to review. The comparison is against text already online, so the figure answers a question about matching sources and is silent on whether a model wrote the words.
Google does have an AI-content checker, just not in Docs. SynthID Detector, announced on 20 May 2025, is a separate verification portal built to identify content made with Google AI by looking for the SynthID watermark. It is a different kind of tool from a text detector, and nothing about it appears inside a Doc. Classroom’s originality reports are a similarity feature too, which our post on whether Google Classroom can detect AI covers.
Tools that plug into Google Docs
Listed in no order of merit. We have not tested the accuracy of any of them for this page; each row records what the vendor’s own page says the integration does, read on 26 September 2026. Where a vendor publishes an accuracy figure we have left it out rather than repeat a number we cannot check.
| Tool | How it runs in Docs | What it reports | Kind | Source (read 26 September 2026) |
|---|---|---|---|---|
| Pangram | Part of the Pangram Chrome extension. Open a Doc and click Scan for AI. | An AI reading plus a playback of how the document was written. | Both | Pangram: AI detection in Google Docs |
| GPTZero | Chrome extension, with an optional auto-scan that runs whenever a Doc is opened. | An AI scan in a side panel, and a Writing Report that rebuilds the edit history and replays it. | Both | GPTZero: Chrome extension for webpages and Google Docs |
| Originality.ai | Chrome extension. | AI and plagiarism scanning, a character-by-character replay, and a flag for non-human typing from auto-typing tools. | Both | Originality.ai Help: Chrome extension |
| Copyleaks | Google Workspace Marketplace add-on, launched from the Extensions menu. | A scan for AI-generated and plagiarised content. The listing describes no replay. | Inference | Copyleaks: AI and Plagiarism Checker, Google Workspace Marketplace |
| Grammarly Authorship | Grammarly browser extension, with Authorship tracking enabled while you write. | Text sorted by where it came from as it arrives: typed, pasted from a browser source or pasted from an unknown source, with separate categories for AI-generated text and for typed text later rephrased by Grammarly's AI or edited with its suggestions. Paid plans add attribution for text copied from generative AI sources, and AI and plagiarism detection inside the report. | Both (AI check on paid plans only) | Grammarly Support: About Grammarly Authorship |
| Brisk (Inspect Writing) | Brisk Chrome extension, while the student writes in Docs as usual. | A replay of how the document was produced, captured while the student writes. Brisk says Inspect Writing gives no accuracy score. | Writing record | Brisk Teaching: Inspect Writing |
| Draftback | Chrome extension, on any Doc the user has edit access to. | A replay of the Doc's revision history. | Writing record | Draftback |
| Turnitin Draft Coach | Add-on opened from Extensions, only if the institution has licensed and configured it. | Similarity, citation and grammar checks. Its FAQ does not mention AI writing detection. | Neither | Turnitin Guides: Turnitin Draft Coach FAQ |
Of the 8, 5 make an AI inference from the text and 6 keep or rebuild a record of the writing; 4 do both, one of them (Grammarly) only on paid plans. Some details behind the rows:
- Pangram’s pricing page lists the browser extension and the Google Docs integration on its free plan. Our Pangram page covers the detector itself.
- GPTZero’s auto-scan matters mostly to students. If whoever opens your Doc has it switched on, GPTZero says the scan has already run and is waiting in their side panel before they ask for it.
- Copyleaks announced the Docs add-on in a blog post dated 9 June 2025; the Marketplace listing shows an update on 25 May 2026.
- The Brisk row covers Inspect Writing, which the Brisk page describes as capturing the process while students write in Docs as usual, and which it says gives no accuracy score.
- Draft Coach is opened from the menu bar via Extensions, then Turnitin Draft Coach, per Turnitin’s guide. It is on this list because students reasonably assume a Turnitin panel inside their Doc shows Turnitin’s AI result. Its FAQ lists similarity, citation and grammar checks and does not mention AI writing detection.
A score and a writing record answer different questions
The Kind column is the one to read first. A detector looks at finished prose and asks whether it resembles machine output. A replay or provenance tool asks something else entirely: how did these words get into this document, in what order, and from where?
Those can disagree without either being broken. An essay typed out slowly over four evenings could still draw a high AI reading, and a replay of it would show the four evenings. Equally, a paragraph composed in a notes app and pasted across arrives in a replay as one block, however human it reads. Grammarly’s categories make the second case concrete: a paste from a private browsing window is logged as coming from an unknown source, which is a description of the paste and not a verdict on it. Our page on Grammarly Authorship goes further into why a record carries more weight than an estimate, and what it still misses.
For a student, the practical upshot is that the record lives in the file. Writing in the Doc you will submit, rather than drafting elsewhere and pasting, is what gives any of the replay tools something to show. How to use that history if your work is questioned is the subject of proving you wrote it, and we will not repeat it here.
Grammarly sits on both sides of that line depending on the plan. Its support article, read on 26 September 2026, says basic Authorship tracking and unlimited reports are available on Free accounts and on Pro, Plus and Premium plans bought through its website. Those paid plans, and Pro, Business, Enterprise and Education accounts bought through Grammarly’s sales team, also show AI and plagiarism checks inside the reports. Grammarly says those checks can flag text that may have been AI-generated even when it was not pasted in, so on a paid plan the report is a record with an inference attached.
Word documents
These 4 could be confirmed on the vendor’s or Microsoft’s own pages. The table is not a complete list of Word add-ins: it holds only what we could confirm at the source, and add-ins we did not check are left out rather than guessed at.
| Tool | Where it runs | What it does | Source (read 26 September 2026) |
|---|---|---|---|
| Word's own Similarity check | Editor, then Similarity, in Word for Microsoft 365 | The share of your text that matches text found online, as a percentage, plus the passages to review. Not an AI reading. | Microsoft Support: Check your document for similarity to online sources |
| GPTZero add-in | Get Add-ins, search GPTZero, then Add | Highlight text inside Word and get an AI result for it. | GPTZero on Microsoft Marketplace (Office add-in) |
| Grammarly Authorship | The Grammarly desktop app for Windows and Mac | The same record of where text came from as in Docs, and on paid plans the same AI and plagiarism checks inside the report. Grammarly says tracked history may become unreliable past 20 pages, and that Grammarly Business team members do not get Authorship in the desktop app by default. | Grammarly Support: About Grammarly Authorship |
| Turnitin Draft Coach | Word for the web only. Turnitin says it cannot be used in desktop Word | Similarity, citations and grammar, as in Docs. | Turnitin Guides: Turnitin Draft Coach FAQ |
The install steps for GPTZero come from its support centre, where the Word articles were marked as last updated about a year before we read them; the Microsoft listing was live on the same day. GPTZero’s Word page calls it the first and only AI detector integrated with Microsoft Word. Grammarly’s desktop app runs Authorship in Word, and its paid plans put an AI check in those reports, so the “first and only” wording is GPTZero’s claim, not a finding of ours.
One gap worth knowing: we could not confirm a Word add-in that runs an AI check from Originality.ai or Copyleaks on either company’s own pages, so neither is in the table.
If the file is going to Turnitin, .docx is on the list of formats its AI writing report accepts. The report’s other conditions apply to Word files as to any other, and they are laid out on our page on PDFs and AI detection.
How a Google Doc reaches your school’s Turnitin
A Doc lives on Google’s servers rather than on your computer, which is where most submission problems start. Turnitin’s guides describe four routes into a standard assignment: drag and drop, upload from your device, upload from Google Drive, or upload from Microsoft OneDrive.
- Drive upload needs third-party cookies. With them blocked, the Google sign-in inside Turnitin fails, according to its file requirements.
- A .gdoc file is not your essay. The same page tells students not to upload one directly, because it holds a pointer to the document online and not the document.
- .odt exports from Google Docs are refused for similarity. Turnitin lists OpenOffice Text files created and downloaded from Google Docs online among those it will not generate Similarity Reports for.
- In Google Classroom, use the Turnitin attachment. Turnitin’s Classroom FAQ says it cannot process files handed in through Classroom’s native submission area, and that similarity checking, AI writing detection and its grading tools all need the Turnitin attachment.
One thing the guides we read leave open: what format a Doc becomes when Turnitin pulls it from Drive. If you want certainty that the AI writing report can read your file, downloading the Doc as .docx or PDF and uploading that removes the question, since both are on the accepted list.
Before submission, Draft Coach is the only Turnitin tool most students will see inside Docs, and what its FAQ describes is similarity, citation and grammar checking, not an AI check. The full picture of what it checks and how access works is in our Draft Coach explainer. What your instructor sees after submission is covered on our Turnitin page.
Where HumanFlow fits, and where it does not
HumanFlow has no Google Docs add-on and no Word add-in. To check a document with us you copy the text out and paste it into our AI detector. It works in English only, so a Doc written in another language is outside what it can read.
Each scan has a word ceiling set by plan: 1,500 words on Free, 5,000 words on Writer, 15,000 words on Studio and 30,000 words on Team. Details are on the pricing page.
Pasting strips the document’s history, so our result is an inference and nothing more. It cannot say how the text was written, and it cannot predict what your institution’s tool will conclude. If a record of your writing is what you need, Draftback or Grammarly Authorship will give you one and we will not. Brisk’s Inspect Writing is left off that list because Brisk pitches it to teachers, as a capture of how students write. If you want a check without leaving the Doc, the extensions in the table do that and we do not. We also sell a rewriting tool, which is a commercial interest on any page about checking, and nothing here should be read as advice to use it to move a score.
Limits of this page
Every row is a vendor describing its own integration, read on one date. Integrations appear, move between plans and disappear without notice, and we did not check which plan unlocks GPTZero’s Writing Report or Originality.ai’s replay. No row here is a measure of whether a tool is right about a given essay.