Copilot vs ChatGPT for Word documents

Copilot is built into Word, Excel, PowerPoint, and Outlook on Microsoft 365 Personal, Premium, and Pro, and for the subscription owner on Family. Microsoft also offers a limited free Copilot, but its Word integration needs an eligible Microsoft 365 subscription.

ChatGPT for Word is an add-in shared with Excel and PowerPoint, available on every ChatGPT plan, including Free, subject to that plan’s usage limits. OpenAI’s pricing page lists the Office extensions as limited on Free and Go and expanded on higher plans. You need access to Word itself to run it. In a work account, the ChatGPT workspace admin and the Microsoft 365 admin can both control whether the add-in is available.

Edge: Copilot is better for eligible Microsoft 365 subscribers, because there is nothing to install. ChatGPT for Word is better for anyone who has Word without a Copilot plan, provided their organization allows the add-in.

In Word, you select text, choose Copilot, and either use Auto Rewrite or describe the change, then pick Replace, Insert below, or Regenerate. In our test, Copilot presented its review findings as cards in the chat pane. When we asked it to fix one, it changed the text directly and marked the change with a blue highlight and an undo button instead of tracked changes.

OpenAI says ChatGPT for Word drafts, summarizes, revises selected text, and adjusts headings, numbering, and formatting, and notes that it can change content you meant to keep, so you should review its edits. Our test covered the standalone ChatGPT app and not the add-in, so we did not see how the add-in marks its edits.

Edge: We can’t say, because we tested Copilot inside Word but tested ChatGPT only through its app.

Both work on the open document inside Word, so the file stays a native Word document. In our test, Word preserved the contract file’s formatting through Copilot’s edits and export. OpenAI says ChatGPT for Word can adjust headings, numbering, and formatting, and warns it can change content you meant to keep. We have no equivalent test of the add-in on the same file.

Edge: We can’t say, because we only tested Copilot inside Word.

Microsoft describes Copilot’s consumer plans as using “AI models selected by Microsoft” without naming them. OpenAI lists which models each ChatGPT plan includes. Free has GPT-5.6 Luna, Plus has GPT-6 reasoning models, and Pro has GPT-6 Astra. That tells you what each plan offers, but the add-in’s help page does not say which model handles a given edit. In our model-only proofreading benchmark, which is not a test of either Word integration, GPT-6 Astra with low reasoning fixed 96.1% of seeded errors.

Edge: ChatGPT, because it publishes which models each plan includes. That makes it easier to know what you are getting, but it is not evidence of better edits.

Copilot in Word comes with Microsoft 365 Personal at $9.99 a month or $99.99 a year, which also pays for Word and the other Office apps. Usage runs on AI credits with feature limits. Family is $12.99 a month (AI for the owner only), and Premium is $19.99. ChatGPT for Word is available on every ChatGPT plan, including Free. The cheapest paid plan is Go at $8 a month, and individual plans are billed monthly. OpenAI says Word usage is priced in tokens at the API rates for the model you use, counts against your plan’s token limits, and draws from the usage allowance shared with Codex and other premium features on plans that include one.

Edge: Copilot is better if you already have an eligible Microsoft 365 plan. ChatGPT for Word is better if you have Word through another license and want to start on the ChatGPT Free plan, within its token limits.