“Should we be using Claude or Copilot?” is the question I get asked more than almost any other right now — usually by an MD who’s noticed half their team quietly pasting things into one AI tool or another and wants to get ahead of it.
Here’s the honest answer up front: it’s the wrong question, or at least an incomplete one. Claude and Microsoft 365 Copilot are both excellent. But they’re not really the same kind of product, so “which is better” depends entirely on what you’re trying to do. This post lays out where each one genuinely wins — and the bit nearly everyone skips, which matters more than the tool you pick.
(For the record: this website, including a fair chunk of this post, is built with heavy AI assistance. So this isn’t an anti-AI piece. It’s a how-to-choose-well piece from people who use these tools every day.)
They’re not the same kind of tool
The single most useful thing to understand before comparing them:
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Microsoft 365 Copilot lives inside the apps you already use — Word, Excel, Outlook, Teams, PowerPoint — and is grounded in your own company data. It can draft an email in your tone, summarise a 40-message Teams thread, or build a deck from a document, because it can see “emails, chats, and documents that you have permission to access” through Microsoft Graph (Microsoft Learn). It only ever surfaces data the individual user already has permission to see.
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Claude is Anthropic’s standalone AI model. You mostly go to it — a chat window, or wired into other software through its API. It doesn’t sit inside your inbox by default. What it’s known for is the quality of its reasoning, writing, long-document work and coding (Anthropic), and a very large context window — current Claude models handle up to a million tokens at once, roughly a 700-page document (Anthropic docs).
So the real question is closer to: do you want AI woven through the tools your whole team already lives in, or do you want a powerful reasoning engine you bring specific heavy work to? Often the answer is both.
Where Microsoft 365 Copilot wins
It’s already where your team works. If you’re a Microsoft 365 business — and most UK SMEs are — Copilot is the path of least resistance. There’s nothing new to learn and nowhere new to log in. It’s the same Word, with a Copilot button.
It knows your business. Because it’s grounded in your tenant, Copilot can answer “what did we agree with this client in March?” or “summarise everything in this project channel,” using your actual emails, files and chats. A general chatbot can’t do that without you pasting the material in by hand.
Procurement is simple. It’s a per-user add-on at £23.10 per user/month on an annual subscription, and it requires a qualifying Microsoft 365 licence underneath it (Microsoft’s UK pricing). One vendor, one bill, one admin centre.
The weaknesses: the value is uneven across a team — it’s transformative for someone who lives in Outlook and Teams, less so for others, and you’re paying per seat regardless. It’s only as good as the state of your data: messy SharePoint permissions and years of sprawl mean messier answers (and occasionally surfacing a file someone shouldn’t have had access to in the first place). And it’s tied to the Microsoft world — great if you’re all-in on 365, less flexible if you’re not.
Where Claude wins
Quality on hard, long jobs. For dense work — analysing a long contract or report, drafting something that has to be genuinely good, structured research, or writing and reviewing code — Claude is frequently the stronger tool. Anthropic positions it as a leading coding model and reports strong scores on independent-style benchmarks like SWE-bench (Anthropic) — though it’s worth reading those as the vendor’s own figures rather than a neutral referee’s.
That huge context window. Feeding Claude an entire policy set, a year of board minutes, or a sprawling spec in one go — and asking questions across all of it — is something it handles comfortably.
It’s not locked to one ecosystem. Claude can be wired into your own tools and workflows through its API. For a business that wants to build something specific — a support-triage assistant, a document checker — that flexibility matters.
The weaknesses: out of the box it doesn’t sit inside your email and files the way Copilot does, so for everyday “make my Tuesday faster” work it’s less seamless for a non-technical team. Pricing is in US dollars — Claude Team is around $20 per seat/month billed annually, with Enterprise priced as a seat fee plus usage (Anthropic) — and getting real value from the API side usually needs someone technical to set it up.
The plot twist: you might not have to choose
Here’s the thing most “Claude vs Copilot” articles miss. In September 2025, Microsoft added Anthropic’s Claude models as an option inside Microsoft 365 Copilot, alongside OpenAI’s (Microsoft; Anthropic). So for some Copilot features you can now have the best of both — Copilot’s grounding in your data, running on Claude’s reasoning.
One caveat that matters for UK and EU businesses: Microsoft states that Anthropic models are processed outside its EU Data Boundary (Microsoft Learn). If data residency is part of your compliance posture, that’s a deliberate decision to make per workload, not a default to flip on without thinking.
The bit everyone skips: data and the law
Choosing the tool is the easy part. The part that actually carries risk is what your team is already doing, and whether it’s safe.
Both vendors are clear about their paid business products: Microsoft says prompts, responses and Graph data “aren’t used to train foundation LLMs” and stay “within the Microsoft 365 service boundary” (Microsoft Learn); Anthropic says that “by default, we will not use your inputs or outputs from our commercial products… to train our models” (Anthropic). On the paid tiers, your data isn’t feeding the machine.
The exposure is almost always the free, consumer versions people use without telling anyone — and they’re using them right now, whether IT knows or not. The NCSC’s guidance on AI chatbots is blunt about it: your queries are visible to the provider, may be stored, and “the terms of use and privacy policy need to be thoroughly understood before asking sensitive questions” (NCSC). And the ICO has been equally clear that there’s no “AI exemption” from data protection law — if staff paste client or personal data into an unapproved tool, that’s still your responsibility (ICO guidance on AI and data protection).
This is the real decision. Not “Claude or Copilot,” but: do you know what your team is using, and is there a policy and a licensed, approved tool so they don’t have to reach for a free one?
So which should you choose?
A simple way to cut it:
- You run on Microsoft 365 and want everyone faster in the tools they already use. Start with Microsoft 365 Copilot. The friction is lowest and the data grounding is the killer feature.
- You have specific heavy lifting — long-document analysis, serious drafting, research, coding, or you want to build your own AI-powered tool. Claude will often do those jobs better, and may be worth it for a handful of power users even if the wider team is on Copilot.
- You’re not sure your data house is in order — sprawling permissions, no AI policy, staff already improvising. Sort that first, whichever tool you land on. A clever assistant on top of messy, over-shared data just surfaces the mess faster.
For most of the businesses we look after, the answer ends up being “Copilot for the team, Claude for specific jobs, and a clear policy underneath both.” There’s no single winner — there’s the right fit for how your business actually works.
If you’d like a straight, no-jargon conversation about where AI fits — which licences make sense, what your team is already using, and how to roll it out without tripping over GDPR — that’s exactly the kind of thing we help with every week.
