Buy the one that can reach the work your people already do. If your business runs on Microsoft 365 (Outlook, Teams, SharePoint, Excel), Microsoft 365 Copilot is the natural first choice: it works inside those apps, on the files and email each person can already open, and the free Copilot Chat that comes with your Microsoft 365 plan lets you start before you pay for anything. If you're on Google Workspace, or a mix of systems, or what you mainly want is a general assistant for writing, research and analysis, ChatGPT Business and Claude Team are both good choices at similar prices. Whichever you pick, buy a business plan. Personal plans are the wrong place for company data.
This is about fit, not which one is cleverest. Models change every few months; where your files live, what staff need to touch and what the contract says about your data change slowly. Those should decide it.
What does each one cost in the UK?
These prices are from each vendor's own UK pricing page as of September 2026, per user per month. Read the VAT wording carefully, because the vendors don't present it the same way.
| Plan | Price per user per month (as of September 2026) | Trains on your data by default? | Admin controls and SSO | Works inside your files? | Best fit |
|---|---|---|---|---|---|
| Microsoft 365 Copilot Chat | Included with eligible Microsoft 365 business plans | No | Microsoft 365 admin centre, work sign-in | Partly: files people upload or open, plus mail in Outlook; otherwise the web | Every Microsoft 365 business, as the starting point |
| Microsoft 365 Copilot Business | £16.10 paid yearly, ex VAT (offer price £13.80 for the first year, new annual commitments 1 July to 31 December 2026, existing customers). Add-on to Business Basic, Standard or Premium, up to 300 seats | No | Microsoft 365 admin centre, Entra ID, your existing sensitivity labels | Yes: inside Word, Excel, PowerPoint, Outlook and Teams, across everything each person can already open | Microsoft 365 businesses with 300 users or fewer |
| Microsoft 365 Copilot | £23.10 paid yearly, ex VAT | No | As above | Yes, as above | Over 300 users, or enterprise Microsoft 365 plans |
| ChatGPT Business (formerly ChatGPT Team) | Standard seat £15 billed annually, £18 monthly; Premium £75 / £90. Teams of 2 to 200. OpenAI's page doesn't say whether VAT is included | No | SAML SSO, MFA, admin console | Through admin-approved connectors (Microsoft 365, Google Workspace, Slack and others), within each person's permissions | General assistant, any mix of systems |
| ChatGPT Enterprise | Price on request (see vendor) | No | Adds SCIM, role-based access, custom retention, UK data residency | As Business | Larger rollouts needing custom terms |
| Claude Team | Standard seat £18 billed annually, £22.50 monthly; Premium £90 / £113. Teams of 2 to 150. Anthropic's UK page says these include 20% VAT | No | SSO, central admin, admin control of connectors | Through admin-approved connectors (Microsoft 365, Google and others), within each person's permissions | General assistant, any mix of systems |
| Claude Enterprise | US$20 per seat billed annually, plus usage at API rates (USD only) | No | Adds SCIM, role-based access, audit logs, custom retention | As Team | Larger rollouts needing audit logs |
| Gemini in Google Workspace | Included in Business Standard, £11.80 on a one-year commitment (Starter: Gmail only). VAT not stated | No, not without your permission | Google Workspace admin console | Yes: inside Gmail, Docs, Sheets and Drive | Businesses on Google Workspace |
Sources, all as of September 2026: Microsoft 365 Copilot UK pricing, Microsoft 365 Copilot enterprise UK page, Microsoft's Copilot privacy documentation and Copilot Chat privacy documentation, ChatGPT pricing and OpenAI's ChatGPT Business FAQ, Claude pricing and Anthropic's Microsoft 365 connector guide, Google Workspace UK pricing and Google's generative AI privacy hub.
The pound figures aren't like for like: Claude's £18 includes VAT (£15 before VAT), Microsoft's exclude it, and OpenAI's page doesn't say, so compare at checkout. Copilot is also an add-on to your Microsoft 365 licence; ChatGPT and Claude are standalone. And every business plan here says it doesn't train on your data by default.
Should we just go with Copilot because we already pay for Microsoft 365?
Often, yes, and not out of loyalty. Copilot's advantage is where it sits. It's inside Word, Excel, Outlook and Teams, and Microsoft's documentation says it "only surfaces organizational data to which individual users have at least view permissions". If your board packs and client files live in SharePoint and OneDrive, that covers the jobs people want done: summarise this thread, draft from last month's pack, find the contract we signed.
The catch is in that same sentence. Copilot respects your permissions, which means it also exposes them. If a salaries folder was shared with everyone by accident years ago, nobody notices, because nobody goes looking. Copilot does. So tidy the sharing on the sites that matter before you switch on paid seats, and start everyone on the free Copilot Chat in the meantime, which works on what people paste, upload or have open rather than reaching across your files.
When do ChatGPT Business or Claude Team make more sense?
When your work doesn't live in Microsoft 365, or people need a general assistant more than one built into documents: Google Workspace businesses, firms whose real work sits in a CRM, and teams that mostly write, research and summarise.
Both can still reach Microsoft 365. OpenAI's SharePoint app and Anthropic's Microsoft 365 connector work within each person's existing permissions and need your Microsoft admin's approval first. But you'll mostly work in their own app and bring files to it, rather than inside Word and Excel.
On paper the two are very close: similar seat prices, no training on business data by default, SSO, admin controls, the same connectors, a two-seat minimum. ChatGPT Business goes up to 200 people, Claude Team to 150. I won't tell you one is smarter; that changes with every release. What you'll feel is how your people get on with it on their own work, which is what the pilot below is for.
Is it safe to let staff use the free or personal versions?
For company data, no. That isn't a judgement about the tools; it's about the terms. OpenAI's pricing page lists "content is used to train our models" as "opt-out available" on Free, Go, Plus and Pro, and "No" on Business and Enterprise. Anthropic's pricing page shows model training as opt-out on Free, Pro and Max, and "none by default" on Team and Enterprise. Personal plans also have no admin console, no single sign-on, and nothing to switch off when someone leaves.
It's happening already. Microsoft UK's research with 2,003 UK employees (October 2025) found 71% had used unapproved consumer AI tools at work, 51% every week, and 28% said their company didn't provide a work-approved option. Giving people an approved one is the simplest fix.
That also settles "ChatGPT Business vs Plus". Plus is £20 a month for one person on OpenAI's UK page as of September 2026. A Business standard seat is £15 billed annually (£18 monthly), with admin, SSO and no training on your data by default. For a company, the business plan is cheaper per head on the prices shown, and safer.
Will it give correct answers about our own numbers?
Only if it can reach clean, consistent numbers. All of them will answer a question about last quarter's margin confidently. Whether the answer is right depends on what they read. If revenue is defined three ways across three spreadsheets, the assistant will pick one, and it won't tell you it had a choice.
UK firms already worry about this. The FSB's June 2026 research found 92% of small firms have some concern about AI risk, and the biggest single concern, at 54%, is AI producing inaccurate responses. Sage's research, published on 23 September 2026, found 42% of UK SMEs say their financial information is too spread out to make better use of AI, and only one in ten can see their full financial picture in one place.
So choosing an assistant and getting to one version of the truth are the same job. If the figures in your board pack come from one agreed set of definitions, any of these tools has something solid to read. If they don't, none of them will fix it (the usual cause is covered in Six Reports, Six Different Numbers). If your numbers live in Power BI and Copilot is on the shortlist, my AI-Ready Power BI Assessment tests whether it will give correct answers against thirty business questions with verified answers, and models the Copilot licence and capacity costs so the bill is a decision rather than a surprise. If you'd rather talk it through first, a free 20-minute call is the place to start.
How do we decide in a week?
You need five people, real work and two honest checks, not a six-month evaluation.
- Pick two, not four. For a Microsoft 365 business, Copilot plus one of ChatGPT Business or Claude Team. For Google Workspace, Gemini plus one of the two.
- Choose five people doing real work. Someone in finance, someone client-facing, someone in operations, a manager who writes a lot, and your biggest sceptic. Give them business seats, not personal accounts. Copilot Business is sold on an annual commitment, while ChatGPT Business and Claude Team can be bought monthly, so a short pilot costs less on those two.
- Use last week's tasks, not demos. Each person redoes three things from last week (the monthly summary, a proposal, the email thread that ate an hour) in both tools, noting time saved and anything wrong.
- Check what it can see. As an ordinary user, ask each tool to find salaries, board papers and HR files. If it finds something it shouldn't, fix the sharing before you buy another seat.
- Check one number. Ask a question about your own figures where you know the answer: last month's revenue, your biggest customer, overdue debt. If the answer is wrong or disagrees with the board pack, the problem is usually the data, not the tool.
- Then buy. Seats for the people who'd miss it, not everyone at once. On Microsoft 365, everyone else keeps the free Copilot Chat.
Common questions
Which is best for a business: ChatGPT, Claude or Copilot?
It depends mostly on where your work lives. A Microsoft 365 business gets the most from Copilot because it works inside Outlook, Teams, Word and Excel on the files each person can already open. On Google Workspace or a mix of systems, ChatGPT Business and Claude Team are close on price and features, so a one-week pilot on real tasks is the fairest way to choose.
Is ChatGPT Business worth it over ChatGPT Plus?
For company use, yes. As of September 2026, OpenAI's UK page shows Plus at £20 a month for one person and a Business standard seat at £15 a month billed annually (£18 monthly), with a two-seat minimum. Business adds SSO, an admin console and no training on your business data by default; on Plus, training is on unless the user opts out.
Do Copilot, ChatGPT or Claude train on our company data?
Not on their business plans, by default. Microsoft says prompts, responses and data accessed through Microsoft Graph aren't used to train foundation models; OpenAI says it doesn't train on ChatGPT Business or Enterprise data by default; Anthropic lists model training as "none by default" on Team and Enterprise. The free and personal plans of ChatGPT and Claude train on conversations unless the user opts out.
How much would Copilot cost for a 50-person business?
At Microsoft's UK price as of September 2026, Microsoft 365 Copilot Business is £16.10 per user per month paid yearly, ex VAT, so 50 seats is £805 a month or £9,660 a year, on top of your Microsoft 365 licences. At the £13.80 offer price for existing customers (new annual commitments, 1 July to 31 December 2026) it's £690 a month. Many start with seats for some people and the free Copilot Chat for the rest.
Can ChatGPT or Claude read our SharePoint and Outlook?
Yes, through connectors. OpenAI's SharePoint app and Anthropic's Microsoft 365 connector both work within each person's existing permissions, and your Microsoft admin has to approve them before anyone can connect. They fetch files on request rather than living inside Word and Excel like Copilot.
Where do we start if our numbers are spread across different systems?
With the numbers, before the AI. An assistant reading three spreadsheets that define revenue three ways will answer confidently from one of them. Agree the definitions behind your board pack, get them into one place everyone uses, and any of these assistants has something reliable to read.