How a UK small business can actually use Microsoft 365 Copilot Chat in 2026

Microsoft 365 Copilot Chat is the free, work-grounded AI assistant that now sits inside most business Microsoft 365 plans, and if you run a UK small business you may already be paying for it without realising. Microsoft confirms the details on its Microsoft 365 Copilot pricing page (checked 19 June 2026): the free Chat tier is included at no extra cost for eligible subscriptions, while the deeper paid add-on that lives inside Word, Excel and Outlook is a separate, ongoing per-seat bill. The two get talked about as if they are the same thing. They are not, and knowing the line between them is the difference between getting useful AI for nothing and quietly signing up for hundreds of pounds a year you may not need.

What you already get for free

Here is the part most small businesses miss. If your team is on a Microsoft 365 Business plan and signs in with work accounts, the free Chat experience is sitting there at m365.cloud.microsoft and in the Microsoft 365 Copilot app. Think of it as a private version of the chatbot you might know from copilot.microsoft.com, except it runs behind your organisation’s protection rather than the open consumer web.

What can it actually do? It writes and rewrites, brainstorms, summarises long documents you paste in, drafts emails and answers questions grounded in a live web search. Say you run a 15-person Leeds agency and a client asks for a quick competitor summary: you can paste in a brief, ask for three positioning angles, and have a first draft in under a minute. It will also work with files you upload into the chat there and then. What it will not do on the free tier is reach into your own Microsoft 365 content on its own, so it cannot answer “what did we quote that client in March” by reading your inbox or SharePoint for you. That reaching-in is the headline paid feature, and I will come to it.

If you have already mapped the wider Copilot range, this is the entry rung of the same ladder I covered in my guide to free Copilot versus Copilot Pro versus Microsoft 365 Copilot, and it pairs naturally with the assistant built into Windows itself, which I walk through in how to use Microsoft Copilot in Windows 11.

What the paid Microsoft 365 Copilot add-on unlocks

The paid upgrade for small firms is Microsoft 365 Copilot Business, aimed at organisations of up to 300 users. Microsoft lists it at £16.10 per user per month on an annual commitment, with a promotional rate of £13.80 running through 30 June 2026, or £19.32 if you pay monthly. It is an add-on, so you still need a qualifying Microsoft 365 base plan underneath it. That is the number that catches people out: the real cost is the add-on plus the seat you are already buying.

For that money you get two things the free tier withholds. First, Copilot lives inside the apps: a side pane in Word that drafts and rewrites against the document you are in, Copilot in Excel that builds formulas and explains a sheet, Copilot in Outlook that summarises a thread and drafts a reply, and Copilot in Teams that recaps a meeting you half-missed. Second, and more important, it grounds its answers in your own work data through what Microsoft calls Work IQ: your files, emails, chats, calendar and the people around you. That is the leap from “clever web chatbot” to “assistant that actually knows your business”. It also adds priority access for faster responses and the ability to build agents with Copilot Studio, which I dug into separately in my piece on how UK small businesses build AI agents in 2026.

If you want the fuller cost-and-rollout picture beyond Chat, I sized up the broader add-on in Microsoft 365 Copilot in the UK: 2026 pricing and whether it is worth it.

The data and privacy boundary you should understand

This is the bit worth slowing down for. Microsoft applies enterprise data protection to both the free Chat and the paid add-on, as long as people are signed in with their work (Entra) accounts. In plain terms: your prompts and the responses are not used to train Microsoft’s foundation models, and the data stays inside your organisation’s tenant protections. That is a meaningfully different posture from a free consumer chatbot, and it is the single biggest reason a cautious small business can let staff use the free Chat without losing sleep.

The free tier is genuinely private for signed-in work accounts. The risk is not Microsoft training on your data; it is your own people pasting client information into the wrong window.

Two caveats keep you honest. The protection depends on staff actually signing in with the work account rather than a personal one, so the consumer Copilot at copilot.microsoft.com does not carry the same guarantees. And data protection is not the same as data governance: under UK GDPR you are still responsible for what personal data your team feeds in. I lay out that thinking in my data protection checklist for SMEs, and while it is framed around a rival tool, the principles travel. Treat AI chat like any other place you would or would not paste a customer’s details.

Microsoft’s own two-minute overview is the clearest plain-English version of where Chat fits, and it is worth a watch before you decide.

One more option sits between free and full: agents. The free Chat can run agents on a metered, pay-as-you-go basis through Copilot Credits, billed only for what you use, with no licence commitment. For a business that wants a single repetitive task automated, that can be far cheaper than buying everyone a full add-on seat.

Two real UK use cases, free versus paid

Let us make this concrete with two illustrative scenarios, not invented case studies. Say you run that 15-person Leeds agency and your team spends Friday afternoons writing proposals. On the free Chat, a strategist can paste a discovery-call summary, ask for a structured proposal outline, and tighten the language, all without exposing anything to the open web. That is real time saved for nothing. The day you want Copilot to read last quarter’s winning proposals straight out of SharePoint and reuse their structure automatically, you have crossed into paid-add-on territory, because that grounding in your own files is exactly what the upgrade buys.

Now picture a small trades firm chasing late invoices. The owner can use free Chat to draft a firm-but-polite payment reminder, then a stronger second-chase version, in seconds. Useful, but they still have to dig out who owes what. With the paid add-on, Copilot in Outlook and Excel can summarise the outstanding-payments thread and pull the figures from the spreadsheet they already keep, turning “remind me who is overdue” into a single question. The free tier helps you write; the paid tier helps you find the thing to write about. That distinction is the whole decision.

If you are weighing Microsoft against the alternatives before committing, this sits alongside my look at how a UK small business can actually use Claude in 2026, my head-to-head on Gemini versus Claude versus Copilot, and the narrower question of which AI email tools are worth it in the UK.

Is Microsoft 365 Copilot Chat worth it for a UK small business?

Here is where I land. For most UK small businesses, the free Chat is a clear yes and you should turn it on this week. It costs nothing you are not already paying, it carries genuine enterprise data protection for signed-in staff, and it removes a real chunk of writing and summarising drudgery. There is no downside to using it beyond the discipline of not pasting client data you should not, and that is a training problem, not a Microsoft problem.

The paid add-on is a different conversation. At £13.80 to £16.10 per user per month on top of your existing licences, it only pays for itself for people who live in Word, Excel, Outlook and Teams all day and who genuinely need Copilot reading their own files to be useful. My honest advice: do not buy it across the whole company. Run the free Chat everywhere, then license the paid add-on for the handful of heavy document-and-inbox roles where the in-app grounding clearly earns its keep, and let the metered agents cover one or two automated tasks for everyone else. That way you capture most of the value of Microsoft 365 Copilot Chat for nothing and pay the premium only where it actually moves the needle. Start free, upgrade narrowly, and ignore anyone telling you it is all or nothing.