Both Microsoft 365 Copilot and ChatGPT Enterprise are powered by large language models developed by OpenAI, yet they are built for fundamentally different purposes. Microsoft has taken the OpenAI technology and embedded it deep inside the productivity applications that hundreds of millions of people already use every day, anchoring it to your organisation's own data. OpenAI, meanwhile, has built a general-purpose AI interface that is remarkably capable across a vast range of tasks — but one that has no inherent knowledge of your business.
This is not a comparison of which product has the "better" AI under the hood — that distinction is increasingly academic as both services run on the same family of frontier models. The real question is architectural: which product is designed to fit inside a business context? And, more specifically, which one fits your business context? The answer depends on your existing technology stack, your compliance requirements, and the kinds of tasks you actually need AI to perform. This guide breaks down every dimension that matters.
The Fundamental Difference: Data Access
Copilot for Microsoft 365 has access to your Microsoft Graph — the unified data layer that connects your emails, Teams conversations, SharePoint documents, calendar, OneDrive files, and more. When you ask Copilot to summarise the key points from last week's project calls, it can actually read those calls. When you ask it to draft a board update based on the latest financial report, it can find and use the correct document from SharePoint. When you ask who said what in a particular email thread three months ago, it knows.
ChatGPT Enterprise does not have this access by default. Without custom API integrations — which require development resource — it operates on the information you paste into the chat window or upload in the session. For point-in-time tasks this is often sufficient. But for the day-to-day productivity tasks that make up the majority of knowledge-worker time — finding information, drafting based on existing context, summarising ongoing projects — the absence of Graph integration is a genuine limitation. ChatGPT Enterprise can be extended via its API and custom GPT functionality, but doing so requires development effort and does not achieve the deep ambient integration that Copilot provides out of the box. See our overview of Copilot licences and plans for the full picture of what each tier unlocks.
"Copilot doesn't just answer your question — it answers it using YOUR data. That changes everything for enterprise users."
Security & Compliance — A Critical Comparison
For UK businesses in regulated sectors — financial services, healthcare, legal, government — compliance is not a checkbox exercise; it determines which tools can be deployed at all. Microsoft 365 Copilot is built on the same compliance infrastructure as the rest of your M365 tenant. That means it inherits all of the policies, sensitivity labels, Conditional Access rules, and data residency commitments you have already established. ChatGPT Enterprise has made substantial progress on enterprise security, but it operates as a separate cloud service with its own compliance posture. Before commissioning a SafeScan security assessment, it is worth understanding exactly where each product stands:
| Feature | Microsoft 365 Copilot | ChatGPT Enterprise |
|---|---|---|
| Data used to train OpenAI models | No | No (Enterprise) |
| Data residency in EU/UK | Yes | Limited |
| Microsoft Purview integration | Yes | No |
| Sensitivity label awareness | Yes | No |
| Conditional Access support | Yes | No |
| SOC 2 Type II | Yes | Yes |
| ISO 27001 | Yes | Yes |
| UK NCSC Cloud Security Principles | Aligned | Partial |
The compliance gap is most visible in three areas. First, Microsoft Purview: Copilot respects the sensitivity labels you have applied to your content. A document marked Confidential will not be surfaced by Copilot to someone who lacks the clearance to view it — the same access controls that govern SharePoint govern Copilot's ability to retrieve and reference data. ChatGPT has no mechanism to enforce these labels. Second, Conditional Access: Copilot is subject to your existing Azure AD Conditional Access policies, meaning you can enforce MFA, device compliance, and location-based access controls at the AI layer — not just at the application layer. Third, data residency: Microsoft commits that M365 data is processed and stored within the tenant's designated geography (UK/EU regions for UK organisations). OpenAI's enterprise data residency commitments are evolving and merit careful review against your organisation's requirements.
Integration & Workflow
Copilot lives in the applications your team already uses every day — Word, Excel, PowerPoint, Outlook, and Teams — as a native, embedded capability. There is no additional tab to open, no separate login, and no context switching. You draft an email in Outlook, highlight a paragraph, and ask Copilot to sharpen the tone. You open a Teams meeting and Copilot is already capturing a live summary. You open a blank PowerPoint and Copilot builds a first-draft deck from the brief you wrote in Word this morning. The friction cost is essentially zero.
ChatGPT Enterprise, by contrast, requires a separate browser tab or a custom API integration. For knowledge workers who already manage multiple applications, adding another interface is not trivial. Research consistently shows that tools requiring context switching are adopted less consistently and used less deeply. For productivity use cases — meeting summaries, email drafting, document creation — Copilot's embedded integration is a significant structural advantage that no amount of model capability can fully offset. Developers and technical teams, however, often find the open interface of ChatGPT more flexible for tasks that do not map neatly to an Office application workflow.
Capability Comparison — What Each Does Best
Capability parity between the two products is closer than it has ever been, and both are advancing rapidly. But there are genuine specialisations that arise from the architectural differences described above.
Copilot for Microsoft 365 excels at:
- Summarising your emails, meetings, and Teams threads — not generic summaries, but ones grounded in your actual organisational context
- Drafting documents and messages in your writing style, drawing on the documents and communications already in your tenant
- Finding information across your files — "what did the legal team say about the GDPR review in February?" — without manual search
- Creating presentation slides directly from briefs, reports, or meeting notes already stored in your M365 environment
- Providing meeting recaps and action items immediately after a Teams call, shared automatically to the relevant channel
ChatGPT Enterprise excels at:
- Open-ended creative tasks — long-form content, brainstorming, ideation — where a clean context window is an advantage rather than a limitation
- Code generation and debugging across a wide range of languages and frameworks, with a large active developer community sharing best practices
- Complex multi-step reasoning tasks that do not require reference to specific organisational documents
- Building custom GPTs for specific departmental workflows, enabling teams to create tailored AI assistants with defined personas and tool access
- Flexible API access for developers building AI-powered products and internal tools
Pricing Comparison (2026)
Pricing for enterprise AI has continued to evolve in 2026, and the headline numbers do not tell the full story. Copilot for Microsoft 365 requires an existing Microsoft 365 E3, E5, or Business licence — meaning the total cost of ownership includes the underlying M365 subscription. For organisations already on M365, this is simply an add-on rather than a net-new infrastructure cost. ChatGPT Enterprise pricing is negotiated annually and requires a minimum seat commitment. The table below reflects current indicative pricing:
- Copilot for Microsoft 365: £30/user/month (requires M365 E3, E5, or Business licence)
- ChatGPT Enterprise: approximately £25/user/month (minimum 150 seats, annual contract)
- ChatGPT Team: £25/user/month (minimum 2 seats — accessible for smaller teams)
- Copilot Studio: £150/month for custom AI agent capability (consumption-based model for extended sessions)
On a pure per-seat basis, ChatGPT Enterprise is somewhat cheaper — but the minimum seat threshold of 150 users makes it practical only for medium-to-large organisations. ChatGPT Team removes this barrier for smaller deployments. Copilot for M365 has no seat minimum, and for organisations that are already paying for M365, the incremental cost is the primary consideration. When evaluating total cost, factor in integration and development costs: Copilot works immediately within your existing environment; extending ChatGPT to connect to your data requires ongoing engineering investment. Our free AI readiness assessment includes a personalised cost-benefit analysis for your specific deployment scenario.
The Verdict — Which Should Your Organisation Choose?
There is no universally correct answer, but the decision framework is relatively clear once you know the right questions to ask.
Choose Copilot for M365 if:
- You are already on Microsoft 365 (E3, E5, or Business Premium)
- Your primary use case is productivity — emails, meetings, documents, slides
- You operate in a regulated sector with compliance requirements (healthcare, finance, government, legal)
- Data residency, Purview, and sensitivity label enforcement are non-negotiable requirements
- You want zero-friction deployment with no additional software or browser tabs
Choose ChatGPT Enterprise if:
- Your team is not primarily Microsoft-based (Google Workspace, Slack, etc.)
- Your primary use case is open-ended — code generation, research, creative content
- You need custom GPTs for specific departmental workflows
- You are a developer team building AI-powered products via API
- You have 150+ seats and want a standalone AI interface separate from your productivity suite
Consider deploying both:
- Many large UK organisations are running both products simultaneously — Copilot for M365 for day-to-day productivity embedded in the tools staff already use, and ChatGPT Enterprise or Team for development teams, marketing creative workflows, and research functions that benefit from an open-ended AI interface
- The two products are genuinely complementary: one is optimised for working with your existing organisational data, the other for open-ended tasks that benefit from a clean context
- If budget requires a choice, prioritise Copilot for M365 if you are an existing Microsoft 365 customer — the integration depth and compliance alignment will deliver more measurable value for the majority of your workforce
If you are uncertain which approach best fits your organisation's workflows, compliance obligations, and existing technology stack, speak to a specialist before committing. The wrong deployment can lead to low adoption, wasted licence spend, and governance gaps. Contact our team for an obligation-free conversation about your AI deployment strategy.
FAQ
Can I use both Microsoft Copilot and ChatGPT in the same organisation?
Yes. Many organisations deploy both — Copilot for Microsoft 365 for day-to-day productivity tasks embedded in their existing tools, and ChatGPT Enterprise or Team for development, research, and creative tasks. They are complementary rather than competing. In practice, most organisations find that Copilot for M365 becomes the primary tool for the majority of staff, while ChatGPT serves specific functions like software development or marketing content creation. A dual deployment is manageable provided you have clear governance policies about what data can be shared in each environment.
Is Microsoft Copilot more secure than ChatGPT for business use?
Microsoft 365 Copilot is built on the same Microsoft security and compliance infrastructure as your existing M365 tenant, including Purview, Conditional Access, and data residency commitments. For organisations with strict compliance requirements — healthcare, financial services, government — Copilot's deep compliance alignment is a significant advantage. ChatGPT Enterprise has strong foundational security (SOC 2 Type II, ISO 27001), but it lacks native integration with Microsoft's information protection controls. This does not make ChatGPT Enterprise insecure; it means that your governance team will need to establish separate controls for it rather than inheriting your existing M365 posture automatically.
Does Microsoft Copilot use my company data to train AI models?
No. Microsoft explicitly commits that your Microsoft 365 data — including prompts, responses, emails, documents, and meeting content — is not used to train the underlying AI models. Your data remains within your tenant's compliance boundary and is not accessible to Microsoft engineers as training material. This commitment is backed by contractual Data Processing Agreements and is auditable through Microsoft's compliance documentation. ChatGPT Enterprise makes the same commitment for enterprise accounts: your conversations are not used to train OpenAI's models.
Is there a free version of Microsoft Copilot for business?
Microsoft Copilot (formerly Bing Chat Enterprise) is available free to Microsoft 365 commercial users and provides web-grounded AI without access to your company data. This free tier gives your team a safe, enterprise-protected AI chatbot for general questions and web research. The full Microsoft 365 Copilot (£30/user/month) unlocks the Microsoft Graph integration — the ability for Copilot to read your emails, meetings, documents, and SharePoint content — which is where the transformative productivity gains are realised. Many organisations start with the free tier to build AI literacy before committing to the paid Copilot licences.