Copilot vs ChatGPT: Which One Fits a Microsoft 365 Office
Short answer: If your company runs on Microsoft 365, you probably already have Copilot Chat at no extra cost: a web-grounded chat with enterprise data protection. The full Microsoft 365 Copilot is a paid add-on that reads your mail, files and calendar. ChatGPT is the more versatile standalone tool. For Microsoft 365 offices, Copilot Chat is the obvious place to start.
The conversation in small companies tends to go like this. The boss has heard about Copilot. The staff have been using ChatGPT for months, often on personal accounts. Nobody is quite sure what the existing Microsoft licence already includes. That last question is the one to answer before buying anything.
What “Copilot” actually means
Microsoft uses the name for several products, which is half the confusion. For offices, three tiers matter, and Microsoft describes them in its Copilot overview.
| Criterion | Copilot Chat (Basic) | M365 Copilot (Basic) | M365 Copilot (Premium) |
|---|---|---|---|
| Extra cost | yes, add-on | ||
| Web-grounded chat | |||
| Copilot in Word, Excel, PowerPoint | partly | ||
| Searches mail, files, calendar itself | |||
| Enterprise Data Protection | |||
| EU Data Boundary |
"Partly" means standard access without priority, subject to capacity.
Source: Microsoft Learn, What is Microsoft Copilot (updated 14 Oct 2026)
Row four is the one that matters. Basic Copilot Chat only knows your company data if you upload a file or have an email or chat open in Outlook or Teams. Only the paid add-on searches your mailbox, OneDrive, SharePoint and calendar on its own. For business plans, Microsoft’s pricing page lists the add-on at $21 per user per month on annual billing, with a promotional $18 until the end of 2026 (as of October 2026). Enterprise agreements have their own terms, so check before budgeting.
Where Copilot clearly wins
Integration is Copilot’s advantage. According to Microsoft, it drafts emails, summarises threads and coaches on tone in Outlook, summarises meetings and captures action items in Teams, and analyses data and suggests formulas in Excel. All of it happens where the work already is. No copying, no switching windows.
The second advantage is the data protection framework. Sign in with a work account and, per Microsoft, prompts and responses get Enterprise Data Protection: the same contractual commitments that cover email in Exchange and files in SharePoint. For EU users there’s the EU Data Boundary on top, which keeps EU traffic inside the EU. For many data protection officers, that settles the argument.
One catch remains. The protection only applies when staff sign in with their work account. Open the same Copilot app with a personal Microsoft account and you’re in the consumer version. Microsoft therefore advises admins to control personal accounts through tenant restrictions rather than blocking the address outright.
Where ChatGPT is the better choice
ChatGPT is more versatile when the job isn’t about Office files. Image generation, a big directory of custom GPTs, a voice mode that holds up in daily use. People in creative or marketing roles often get there faster with it.
For freelancers without a Microsoft 365 business licence, the question looks different anyway. There’s no Copilot Chat with enterprise protections, so ChatGPT or a similar assistant is the simpler route. How it stacks up against Claude is covered in our ChatGPT vs Claude comparison.
Which models run underneath
People often ask whether Copilot is “worse” than ChatGPT because it just borrows the same technology. That’s no longer accurate. Microsoft describes a model selector with Auto, Quick response and Think deeper options. On Auto, a router picks a fast or a more deliberate model depending on the question. For licensed versions, Microsoft says Anthropic models can also be used, operating under Microsoft’s data protection commitments.
The upshot: answer quality is in the same league for both products. Data access and interface, along with contract terms, make the difference, not raw model intelligence.
The overlooked risk: Copilot finds everything
Here’s something many companies only notice after rollout. Premium Copilot searches everything the signed-in user has permission to see. If a salary spreadsheet in SharePoint has accidentally been shared with the whole company, Copilot will surface it when someone asks “What does the sales team earn?”
Copilot doesn’t bypass permissions. It exposes sharing mistakes that were already there and used to stay buried. Microsoft’s own documentation points to tools for reducing oversharing before rollout.
- Review SharePoint and Teams sites shared with "everyone in the organisation"
- Lock down folders with HR, payroll or health data
- Archive or delete old project sites
- Apply sensitivity labels to confidential documents
- Start with a small pilot group, then widen
ChatGPT doesn’t have this problem in the same form, because it doesn’t trawl your file storage automatically. It has a different one: staff paste data in, and when that happens through personal accounts, the company loses control. Our ChatGPT and GDPR guide explains the legal side.
A simple way to decide
Most small companies fall into one of three situations.
You’re on Microsoft 365 Business with most documents in SharePoint and OneDrive. Start with Copilot Chat, since it costs nothing extra and brings the data protection framework. Trial the premium add-on with two or three people who live in email and meetings, then decide after a month.
You’re on Google Workspace, or a mix. Copilot barely matters here. Team plans from ChatGPT, Claude or Gemini fit better.
You work alone. Then it mostly comes down to which tool you enjoy using. An individual plan around $20 a month is plenty, with training switched off if client data is involved.
How to judge a one-month trial
Whether the premium add-on pays off won’t show in the marketing. It shows in your week. Three questions are enough.
How often was it actually used? Microsoft gives admins usage reports showing active days and prompt counts. Anyone asking only a couple of times a week after four weeks doesn’t need the licence.
Which tasks got faster? Ask testers to write down two or three concrete cases, such as “meeting recap instead of my own notes” or “reply to a long email chain in five minutes rather than twenty”. Specific examples beat a vague feeling.
What went wrong? Wrong summaries, documents that shouldn’t have appeared, answers with invented details. Each case is valuable, because it shows where rules or sharing settings need tightening.
What to agree on, whichever you choose
If both tools are allowed side by side, write a one-line rule about which data goes where. Something like “client data only in Copilot with a work account; ChatGPT only for text with no personal data” heads off most problems. Companies in the EU also have an AI literacy obligation under the AI Act; our piece on AI Act AI literacy explains what that means in practice.
And if neither Copilot nor ChatGPT can reach the systems that matter to you, such as industry software or your own database, you need something custom. That is what a development partner like OnlineBuilders builds.
The next step takes five minutes. Open copilot.cloud.microsoft with your work account and see which Copilot tier it shows you. Other tool comparisons are under tools.
Questions people ask
Is Copilot just ChatGPT with a different logo?
No. Copilot uses large language models including OpenAI's, and Microsoft's documentation says licensed versions can now also draw on Anthropic models. It's a separate product with its own data connections and contract terms.
Is Copilot Chat really free?
It's included at no extra charge with eligible Microsoft 365 business licences. Letting it search your mail and files through Microsoft Graph requires the paid add-on.
Which is safer for company data?
Signed in with a work account, Copilot falls under Microsoft's Enterprise Data Protection and, for EU users, the EU Data Boundary. ChatGPT Business also keeps training off by default and offers a data processing agreement. A personal ChatGPT account is the worst option for company data.
Can we use both?
Many companies do. Write down a simple rule about which data goes where, so client information doesn't end up in someone's personal account.
