ChatGPT, Microsoft 365 Copilot or Gemini for a small business: price, training on your data, and who controls what

As each vendor's own pages showed them on 30 October 2026. Prices are per user a month, in euro, from the Irish pages.

When this comparison was made, OpenAI's pricing page, its business pages, its policy pages and its help centre all answered with a browser check, which was not worked around. That leaves the price of ChatGPT's business plans and the settings of its Business plan unread here. Read them on OpenAI's own pricing page before you buy.

Two OpenAI pages could be read. Its trust portal, which describes ChatGPT Enterprise and ChatGPT Edu, says that by default OpenAI does not use ChatGPT Enterprise, ChatGPT Edu or API inputs and outputs to train its models; that data may be processed or stored in the locations on its subprocessor list; that eligible Enterprise and Edu customers can choose a supported region for storing covered content; and that workspace administrators on those plans control how long chats are kept. It lists ISO 27001, 27017, 27018, 27701 and 42001 certificates and a SOC 2 Type 2 report.

The form OpenAI uses to sign its Data Processing Addendum says the agreement applies to its business offerings, naming ChatGPT Enterprise, ChatGPT Team and the APIs, and not to its consumer services, among which it names ChatGPT itself. It also says OpenAI cannot review or sign a customer's own agreement, or change its own case by case.

On its Irish page for small businesses in October 2026, Microsoft sold Copilot two ways: as the Microsoft 365 Copilot Business add-on, at €18.20 per user a month paid yearly with a promotional €15.60 for the first year, or as Microsoft 365 plans with Copilot built in: Business Standard with Copilot (€20.36) and Business Premium with Copilot (€27.73), as listed with Teams. All three are annual subscriptions that renew automatically, and the prices exclude VAT. The add-on is only for existing Microsoft 365 customers on an eligible Business plan, and Microsoft says some advanced AI features are billed by usage on top of the licence.

Microsoft's documentation says Copilot only shows a user data they already have at least view permission to, so a SharePoint site shared with everyone becomes something anyone can ask about. Microsoft Copilot and the GDPR covers that, the EU Data Boundary and what to check before switching it on.

Google includes Gemini in its Workspace Business plans. On the Irish page, Business Starter lists the Gemini assistant in Gmail and chat with Gemini, with the line that company data is not used to train models; Business Standard lists the assistant in Gmail, Docs, Meet and more. Google shows two prices per user a month for each plan, in euro and billed monthly: €8.10, €16.20 and €25.30, and €6.80, €13.60 and €21.10 with the one-year commitment the page says saves 16%. Business plans are limited to 300 users. The page does not say whether VAT is included.

Google's privacy hub for Gemini says your content is not human reviewed or used to train generative AI models outside your domain without permission. The Gemini app is on by default and admins can switch it off; on supported editions they can also turn Gemini features on or off in each Workspace app. Admins choose how long Gemini app conversations are kept: the automatic deletion options are 3, 18 or 36 months, and the default is 18. The data region setting that lets an admin store Gemini prompts and responses in the EU comes with Business Standard and Plus, not Starter, and Google's research notebook, Gemini Notebook, is outside data regions altogether.

The first question is which email and documents you already run. Copilot and Gemini work on the mail, files and calendars already inside Microsoft 365 or Google Workspace, under the terms that already cover them, and both show each person only what they are allowed to open. ChatGPT is a separate service, with its own accounts and its own terms. If you have not settled that first question, Google Workspace or Microsoft 365 compares the two suites.

On cost, Gemini comes with every Workspace Business plan, and Copilot is either an add-on to Microsoft 365 or a Microsoft 365 plan with it built in. ChatGPT's price has to be read from OpenAI's own page.

Whichever you choose, put staff on business accounts, not personal ones: the no-training statements and the data processing terms above are written for the business plans. Where the provider processes personal data on your behalf, Article 28(3) of the GDPR requires a contract with set terms, and each vendor's agreement is the one to file. What a data processing agreement must contain is the checklist to read it against.

The rest belongs in a written policy: which tool is approved, what may be typed into it, and who checks what it produces. The AI use policy for a small business sets out what the EU AI Act and the GDPR ask of a business whose staff use AI, with a policy to adopt.