The short answer
If your company runs entirely on Microsoft 365 and you want AI inside Outlook, Word, Teams and SharePoint, Microsoft 365 Copilot is the logical choice. If you want the strongest general model, custom GPTs and a fast start, ChatGPT Business is. Copilot wins on integration, ChatGPT on freedom and model quality.
The difference in one table
| Microsoft 365 Copilot | ChatGPT Business | |
|---|---|---|
| Price indication | Around 21 dollars per user, on top of an existing Microsoft 365 subscription | Around 20 to 25 dollars per user, with no further requirements |
| Requires | A valid Microsoft 365 subscription; it cannot be bought standalone | Nothing, it works alongside your existing software |
| Strongest point | Sits inside Outlook, Word, Excel, Teams and SharePoint and knows your own documents | Stronger general models, custom GPTs, projects and file knowledge |
| Weakest point | Quality depends on how clean your SharePoint and permissions are | Knows your company files only if you supply or connect them |
| Suits | Organisations already running fully on Microsoft | Teams that want to move fast and are not tied to one suite |
When Copilot
Choose Microsoft 365 Copilot when your mail, documents and collaboration already live in Microsoft 365 and you mainly want AI to think along inside those windows. The gain is that nothing has to be moved: Copilot reads the documents your people already work in.
There is a condition that often gets skipped. Copilot inherits both the permissions and the mess of your SharePoint. If documents are open that should have been restricted, Copilot will find those too. Clean that up first.
When ChatGPT
Choose ChatGPT Business when you want the strongest general model, want custom GPTs for recurring tasks, or when your company does not run fully on Microsoft. It stands alone, you can be live tomorrow, and you are tied to nothing.
With ChatGPT Team and Enterprise you sign a data processing agreement, training on your data is off by default, and you can choose storage inside Europe. That is exactly what you need as soon as customer data comes into play. More about that on the page about customer data in ChatGPT.
When neither is enough
Both are chat windows. They wait until someone asks something. Work that comes back every week in fixed steps needs something else: a workflow that runs by itself, with fixed sources, an owner, an approval step and a log. If work piles up because nobody starts it, a licence will not solve that.
That is where AI automation starts and where a chat window stops. In practice I often use both: the model for the thinking, the workflow for the repetition.
Frequently asked questions
Can I buy Copilot separately from Microsoft 365?
No. Microsoft 365 Copilot requires a valid Microsoft 365 or Office 365 subscription per user. The Copilot price comes on top of that, so your total cost depends on what you already pay.
Is ChatGPT safe enough for company data?
With ChatGPT Business or Enterprise you sign a data processing agreement, training on your data is off by default, and you can choose storage inside Europe. With a free or personal account you have none of those three.
Do I have to choose, or can I run both?
You can run both, and for many companies that is the wisest option: Copilot for work inside Microsoft, ChatGPT for heavier thinking and custom GPTs. Budget for two licences per person in that case.
What if neither solves my problem?
Then your problem is probably not a missing chat window but a process that keeps piling up. Start with the free process diagnosis: you hear which process is suitable, which tools fit and what it is worth.
