Microsoft 365 Copilot vs ChatGPT Business and ChatGPT Enterprise

1. Turn on Microsoft 365 Copilot Chat for everyone. Microsoft's pricing page lists it as available at no additional cost with eligible Microsoft 365 plans, and it is the sanctioned alternative to a personal ChatGPT account for work data.
2. Buy Microsoft 365 Copilot, or Copilot Business if you are on a Business plan with up to 300 users, for the roles whose work lives in Outlook, Teams, Word and Excel, after the oversharing review and a measured pilot.
3. Buy ChatGPT Enterprise, not ChatGPT Business, for a team that needs OpenAI's models, custom GPTs or heavy research and writing, and connect the workspace to Purview on day one.
4. Do not make ChatGPT Business the organization's AI platform if you are regulated. Microsoft's Purview integration applies only to the Enterprise edition, so a Business workspace sits outside your audit, retention and eDiscovery.
5. Budget separately for agents, which Microsoft meters outside the seat.

Microsoft list price, October 2026 price list, per user, billed to you by Microsoft. OpenAI's prices are OpenAI's to quote and are not printed here.

Microsoft's training material lists the qualifying base plans as Microsoft 365 E3 and E5, Office 365 E3 and E5, Business Basic, Standard and Premium, Microsoft 365 Apps for business and enterprise, and Microsoft 365 F1 and F3; Copilot licensing and pricing covers the prerequisites in full.

Microsoft. The enterprise data protection page on Microsoft Learn states that prompts, responses and data accessed through Microsoft Graph are not used to train foundation models. Web queries sent to Bing go with user and tenant identifiers removed, are not shared with advertisers and are not used to train Microsoft's foundation models. These protections apply when a user is signed in with a work or school account; the consumer Copilot is a different product with different terms.

OpenAI. OpenAI's help center states that with ChatGPT Business, ChatGPT Enterprise, ChatGPT Edu and the API platform, OpenAI does not, by default, use provided inputs and outputs to train its models. The same article says data sharing is enabled by default on Free, Plus and Pro personal workspaces, with an opt-out.

Side by side, the two business promises are close. The organizational risk is not the vendor's training policy; it is the employee using a personal Free or Plus account where training is on by default. That is why step one of the pattern is Copilot Chat for everyone, and why controlling shadow AI with Purview comes before any seat purchase.

The table is the whole decision for a regulated organization. Copilot is a Microsoft 365 workload and inherits every control you already run. ChatGPT Enterprise can be brought into the same Purview portal for audit and discovery, but not for blocking. ChatGPT Business cannot be brought in at all.

Microsoft 365 Copilot answers from your mail, files, chats and meetings through what Microsoft calls Work IQ, under the permissions each user already has. That is why the first Copilot problem in every tenant is oversharing: Copilot finds the spreadsheet a user could always open but never did. Copilot oversharing and why Purview comes before Copilot are the preparation.

ChatGPT has been closing the gap. OpenAI's help center says SharePoint connectors are available on Pro, Business and Enterprise/Edu plans. Admins can either deploy SharePoint sync for all users in the workspace (Enterprise/Edu only) or allow individual users to connect their own accounts through OAuth, and role-based access to connectors is Enterprise/Edu only. Some Outlook, Teams and SharePoint actions require Microsoft Graph permissions that a Microsoft Entra administrator must grant for the organization, and as of 30 April 2026 the admin-managed sync option uses Microsoft application scopes rather than delegated scopes.

Three consequences: the oversharing review applies to both products, because a connector respects existing permissions and therefore exposes existing mistakes; with a connector authorized, tenant content is processed under OpenAI's terms outside the Microsoft 365 boundary, which is a decision to make in writing; and Entra admin consent is your control point, so review enterprise application consents monthly and block user consent to unverified apps.

Microsoft's documentation describes registering a ChatGPT Enterprise workspace as a Purview data source so prompts and responses land in the unified audit log and the rest of the Purview set.

1. In the Azure portal, create a Key Vault, assign the roles Microsoft lists, and store the ChatGPT Enterprise API key as a secret; Purview authenticates to the workspace with OAuth 2.0.
2. In the Purview portal, register the workspace as a data source and configure the scan. Since May 2025 these scans use Purview's pay-as-you-go billing, so enable it on an Azure subscription; the charge is Microsoft's, on your bill.
3. In Data Security Posture Management for AI, create the collection policy. Microsoft's Tech Community post states that from 19 May 2025 a collection policy is required to ingest ChatGPT Enterprise interactions, and that it is a one-click setup there.
4. Allow at least 24 hours for the policy to collect data, then confirm prompts and responses in Audit search.
5. Add the workspace to your eDiscovery, retention, insider risk and communication compliance policies as needed.

What this does not give you: sensitivity label enforcement, encryption or DLP blocking inside ChatGPT. It captures after the fact. If the requirement is to stop a labeled document from being processed, only Copilot's DLP location does that today.

Size the Copilot count with the Copilot ROI calculator and a 30-day pilot (how to run one); the seat count that survives the pilot is usually a third to a half of the one proposed before it.

1. Readiness. The Microsoft 365 Copilot readiness assessment, $4,950, checks licensing prerequisites, identity, data labels and the sharing posture.
2. Oversharing. The oversharing assessment and remediation, $4,950 per project, fixes what Copilot and any connector would expose.
3. Use cases. The Copilot and AI use-case ROI sprint, $3,950 per project over two weeks, scores candidate uses on value, effort, data readiness and risk and returns three costed use cases with a 90-day plan; it is where the ChatGPT Enterprise question gets answered with evidence.
4. Seats. Deployment and adoption at $45 per user with a $4,000 minimum, then training and prompt workshops at $1,450 per day.
5. Agents. Agents used through Copilot Chat are metered; set the budget and alert before the first one ships.
6. Review. Managed Copilot adoption, $6 per user per month, reassigns idle seats monthly.

All project work is quoted in writing before it begins; Microsoft licenses and metered agent usage are billed to you by Microsoft.

Is Microsoft 365 Copilot safer than ChatGPT?

The training promises are similar for the business plans. Copilot keeps prompts and responses inside your Microsoft 365 tenant under your existing audit, retention, labels and DLP. ChatGPT Enterprise can be connected to Purview for audit and discovery but not for blocking; ChatGPT Business cannot be connected at all.

Can Purview see ChatGPT conversations?

For ChatGPT Enterprise, yes, once the workspace is registered as a Purview data source with its API key and a collection policy exists in DSPM for AI; prompts and responses then appear in the audit log, eDiscovery and retention. Microsoft states the integration applies only to the Enterprise edition, so not for ChatGPT Business or personal accounts.

Is Copilot Chat really included?

Microsoft's pricing page lists Microsoft 365 Copilot Chat as available at no additional cost with eligible Microsoft 365 plans. The limit is what it can see: the web and the files a user gives it, not the tenant at large. Organization-built agents used through it are metered.

Should a 30-person company buy ChatGPT Business or Copilot Business?

If the work is in Outlook, Teams, Word and Excel, Copilot Business at $252 per user per year (Microsoft list price, October 2026 price list) reads your content under your existing controls. ChatGPT Business suits a small unregulated team that prefers OpenAI's models and has no audit requirement.

Does ChatGPT train on our data?

Not by default on ChatGPT Business, ChatGPT Enterprise, ChatGPT Edu or the API, according to OpenAI's help center. Free, Plus and Pro personal accounts share data for training by default unless the user opts out, which is why personal accounts are the risk to manage.

Do we need Purview before buying Copilot?

You need the oversharing review and the labels that matter before the first seat; Copilot surfaces whatever a user can already open. Purview DLP with Copilot as a location is the control that keeps labeled documents out of Copilot's processing, and it needs the labels to exist first.

• Microsoft Copilot plans and pricing — Microsoft, checked 2026-10-11
• Enterprise data protection in Microsoft 365 Copilot and Microsoft 365 Copilot Chat — Microsoft Learn, checked 2026-10-11
• Use Microsoft Purview to manage data security and compliance for ChatGPT Enterprise — Microsoft Learn, checked 2026-10-11
• Archive ChatGPT Enterprise interactions in Microsoft Purview — Microsoft Learn, checked 2026-10-11
• Assign your Microsoft 365 Copilot licenses — Microsoft Learn training, checked 2026-10-11
• MC1059677: Data Loss Prevention, restrict Copilot in Office from processing labeled content — Microsoft 365 Message Center, archived by Merill Fernando, checked 2026-10-11
• ChatGPT Business rename FAQ — OpenAI Help Center, checked 2026-10-11
• What if I want to keep my history on but disable model training? — OpenAI Help Center, checked 2026-10-11
• New compliance and administrative tools for ChatGPT Enterprise — OpenAI, checked 2026-10-11
• SharePoint synced connectors setup — OpenAI Help Center, checked 2026-10-11