Copilot vs ChatGPT: built into Microsoft 365, or a separate assistant?

These two get compared because both are called an AI assistant, but they solve different problems. One is built into the software many offices already run on. The other is a separate product you go to. The choice depends less on model quality than on your data, your admin and your workflow. Facts below come from Microsoft’s and OpenAI’s own pages as of November 2026, and where a fact could not be confirmed it is left out.

Comparison table

	Microsoft Copilot	ChatGPT
Where it lives	Inside Word, Excel, PowerPoint, Outlook and Teams	Web, desktop and mobile apps, plus API
What it can see	Content in Microsoft Graph that the user already has access to: organizational data to which individual users have at least view permissions	Whatever you upload or paste, plus any connectors you enable
Naming	Microsoft documents Microsoft Copilot Chat and Microsoft Copilot as experiences that differ by data grounding, integration depth, and licensing	ChatGPT plans include Free, Go, Plus, Pro, Business, Edu and Enterprise
Pricing structure	The Copilot Business add-on is available only to existing Microsoft 365 customers with an eligible Business plan; $18 per user per month on annual billing, originally $21 (discount offer available July 1 to December 31, 2026, first year only) and $25.20 monthly	Plus is $20 per month; Business seat pricing: check OpenAI
Data and training	Microsoft states that prompts, responses, and data accessed through Microsoft Graph are not used to train foundation LLMs	Check the data controls and the terms of your plan
Admin	Admins can use Microsoft Purview to set retention policies for Copilot chat interactions	Business and Enterprise plans have admin features
Models	Microsoft documents that Anthropic subprocessors are available only in applicable Microsoft 365 licensed experiences	OpenAI models
Learning curve	Low if you use the Microsoft apps daily	Low

Copilot prices vary with which Microsoft 365 plan you have and whether you buy the add-on or a bundle, so check Microsoft’s pricing page for your situation.

Where Copilot is stronger

Your data is already there. Copilot grounds answers in your emails, meetings and files, respecting the permissions users already have. Asking “what did we decide about the Q3 vendor renewal in last week’s threads” works because it can reach those threads. With a standalone assistant, you have to bring the material to it.

Inside the document. Drafting in Word, summarizing an Outlook thread, and building a slide deck from a document all happen without leaving the app. For Excel specifically, see the AI with Excel guide.

Central control. Microsoft’s documentation describes retention policies via Purview and says Copilot only surfaces data a user already has permission to view. IT teams that already manage Microsoft 365 find this easier to govern.

Where ChatGPT is stronger

Flexibility. It is not tied to a suite. If half your work is in Google Workspace, Notion or plain files, a standalone assistant fits better.

Access without a license conversation. You can start on a personal plan today. Whether you should is a different question; see is it safe to put company data in ChatGPT.

Agent tools. ChatGPT plans include Codex for multi-step tasks. Copilot has its own agents, but the two are different products.

The permissions caveat

Because Copilot reaches into your Microsoft 365 content, it can surface anything a user has access to, including files shared too broadly years ago. Microsoft’s privacy documentation says it is important to use the permission models available in Microsoft 365 correctly. Clean up sharing before a broad rollout, or you may find that Copilot makes bad permissions visible.

Trade-offs

• Cost structure. Copilot is typically a per-user add-on on top of Microsoft 365, so the total is higher than the add-on price alone.
• Ecosystem dependence. The benefit largely disappears outside Microsoft’s apps.
• Both can be wrong. Review what either one writes before it goes out.
• Both change quickly. Names, plans and prices in this area have shifted more than once.

A quick way to test both

Pick one real document from your week, such as a long email thread with a decision buried in it. In Copilot, ask it to summarize the thread and list the decisions and open questions. In ChatGPT, paste the same thread, without anything confidential, and ask the same. Compare how much correction each output needs, and note how much effort it took to give each the context. That effort, more than the polish of the answer, is usually what decides which one you reach for on a busy day.

How to choose

Ask three questions. Where do your documents and email live? Does your employer license Copilot? And what does your policy say about personal AI accounts? If the answers are Microsoft 365, yes, and restrictive, use Copilot for company work. If you want a general assistant for writing, analysis and building tools, ChatGPT or Claude is the alternative. See the Copilot glossary entry for the naming background.

What the vendors’ pages say

Each line below is taken from Microsoft’s or OpenAI’s own documentation, quoted in the Sources list.

• Microsoft Copilot only surfaces organizational data to which individual users have at least view permissions
• Prompts, responses, and data accessed through Microsoft Graph aren’t used to train foundation LLMs, including those used by Microsoft Copilot
• Microsoft Purview admins can set retention policies for the data related to chat interactions with Copilot
• Microsoft Copilot is available with Microsoft 365 E7 or as an add-on for eligible commercial, US Government, and education subscription plans
• Anthropic subprocessors are available only in applicable Microsoft 365 licensed experiences and are not available to all users by default
• The Codex pricing page lists ChatGPT Plus at $20 per month for a few focused coding sessions each week
• Codex is included in the ChatGPT Free, Go, Plus, Pro, Business, Edu and Enterprise plans

Learn AI Fast is a two-day in-person class in Boston that covers Copilot alongside Claude Code, Codex, OpenClaw and Perplexity, so you can see which fits your work.

Sources

• Microsoft Learn, Microsoft 365 Copilot privacy: “Microsoft Copilot only surfaces organizational data to which individual users have at least view permissions”
• Microsoft Learn, Microsoft 365 Copilot privacy: “Prompts, responses, and data accessed through Microsoft Graph aren’t used to train foundation LLMs, including those used by Microsoft Copilot”
• Microsoft Learn, Microsoft 365 Copilot privacy: “Admins can also use Microsoft Purview to set retention policies for the data related to chat interactions with Copilot”
• Microsoft Learn, License options for Microsoft Copilot: “Microsoft Copilot is available with Microsoft 365 E7 or as an add-on for eligible commercial, US Government, and education subscription plans”
• Microsoft Learn, Microsoft 365 Copilot overview: “Anthropic subprocessors are available only in applicable Microsoft 365 licensed experiences and aren’t available to all users by default”
• OpenAI, Codex pricing: “Power a few focused coding sessions each week. $20 /month Get Plus”
• OpenAI, Codex pricing: “ChatGPT Work and Codex are included in your ChatGPT Free, Go, Plus, Pro, Business, Edu, or Enterprise plan”