Microsoft Copilot for Law Firms: Is It Worth It?

Microsoft 365 Copilot is AI built into Outlook, Word, Teams and the rest of Microsoft 365. For law firms that already run on Microsoft, it can be the easiest way to bring AI into daily work. But it only pays off if your data is in good order and your people know how to use it.

This guide explains what Copilot does for lawyers, what it costs, the risk most firms miss, and how to decide if it is right for your firm.

What Copilot does for lawyers

• Email. Summarise long threads in Outlook and draft replies in seconds.
• Documents. Draft, rewrite and summarise in Word, using your existing files as a starting point.
• Meetings. Get notes, actions and summaries from Teams calls.
• Finding things. Ask questions across your emails, files and chats instead of searching folders.
• Spreadsheets. Analyse figures in Excel, such as costs, completion data or billing reports. The big advantage is that it works where your lawyers already are. There is no new app to learn.

Copilot Chat or full Copilot?

Microsoft offers two quite different things under the Copilot name, and firms often confuse them.

• Copilot Chat. A chat assistant available to many Microsoft 365 business users at no extra cost. When staff sign in with their work account, it comes with Microsoft's business data protections. But it does not work across your emails, files and Teams chats the way the full licence does.
• Microsoft 365 Copilot. The paid licence. This is the version built into Outlook, Word, Excel and Teams that can see and work with your firm's own content. Copilot Chat can be a sensible, low cost first step. The full licence is where the real time savings come from, and also where the main risk sits.

What Copilot costs

• Copilot Business. For organisations with up to 300 users. It has the same features as the enterprise version and lists at around $21 per user per month on annual billing, or around £16 in the UK. There is no minimum number of seats.
• Microsoft 365 Copilot (enterprise). For larger organisations, at around $30 per user per month. Both sit on top of a qualifying Microsoft 365 plan, such as Business Standard or Business Premium. Microsoft also sells bundles that include Copilot, and prices change often, so check the current figures before you buy.

The risk most firms miss

Copilot can see whatever each user already has access to in Microsoft 365. If your permissions are messy, Copilot will surface that mess. A trainee could find a partner's confidential file, an HR record or another client's matter simply by asking a question.

This is not a flaw in Copilot. It is the result of years of shared folders, open Teams sites and "anyone in the firm" sharing links. Copilot just makes it easy to find.

Before switching Copilot on, firms should:

• Review who can access what. Check SharePoint sites, folders and Teams, especially for sensitive matters.
• Lock down sensitive areas. HR, partner, finance and high profile client files should be restricted.
• Fix open sharing links. Links shared with the whole firm are a common problem.
• Use sensitivity labels where your Microsoft plan supports them, so confidential documents are marked and protected.
• Respect information barriers. If you run conflict walls between teams, make sure they are reflected in Microsoft 365 permissions.
• Agree a short AI policy so staff know how Copilot outputs are checked. See our guide to AI policy for law firms. Get this right first and Copilot becomes much safer and more useful. An AI readiness assessment includes this review.

What the SRA expects

The SRA's August 2026 warning notice makes clear that solicitors remain responsible for anything produced with AI, and that client information should only go into AI systems with proper safeguards. Copilot keeps data inside your Microsoft environment, which helps. But if Copilot shows a fee earner a document they should not see, that is still a confidentiality problem for the firm. The Upper Tribunal has suggested Copilot avoids the risks of public AI tools, but as we explain in our analysis of UKUT 81, what matters is the plan and the contract, not the brand.

Copilot, ChatGPT or Claude?

Copilot suits firms that live in Outlook and Word and want AI inside those tools. Claude often stands out for long documents and careful writing. ChatGPT is the best known with a broad set of features. Some firms use Copilot for everyday email and documents and a second tool for heavier document work.

Is Copilot worth the cost?

Copilot is licensed per user, so rolling it out to everyone at once can be expensive. A better approach:

1. Fix permissions first. This is the step most firms skip, and the one that matters most.
2. Start with a pilot. Ten to twenty users across a few teams.
3. Pick clear tasks. Email triage, meeting notes and first drafts.
4. Train people properly. Most of the value comes from knowing what to ask. See AI training for solicitors.
5. Measure the time saved. Then decide who really needs a licence.