Microsoft Copilot for accountants: what to use it for, and what to check

First: which Copilot are you using?

Microsoft uses the Copilot name for more than one product, and the difference matters for client data.

• Copilot for work. As used by organizations, Microsoft Copilot and Microsoft Copilot Chat are covered by Microsoft's Data Protection Addendum and Product Terms, with Microsoft acting as a data processor. Microsoft says prompts and responses aren't used to train its foundation models, and that your organization's retention policies and audit apply (Microsoft).
• Copilot on a personal account. Those organizational commitments come from your employer's agreement with Microsoft. Signed in with a personal Microsoft account, you're outside it, so don't use it for work data.
• Web searches. When Copilot searches the web, the search queries go to Bing under separate terms. Microsoft says they're sent with user and tenant identifiers removed.

Even with the work version, your firm's policy and your professional duties decide what can go in. The client data guide covers the AICPA confidentiality rule and IRC §7216. Which Copilot features you see depends on your Microsoft 365 plan and your organization's settings.

In Excel: formulas and first-pass analysis

Microsoft says Copilot in Excel can create and explain formulas, answer questions about your data with charts, PivotTables, summaries, trends and outliers, and apply sorting, filtering and conditional formatting (Microsoft). Good uses for accountants:

• writing a SUMIFS or XLOOKUP for a schedule;
• a first look at a GL export: the largest movements, unusual vendors, round-number entries;
• a PivotTable of expenses by vendor or by month;
• flagging possible duplicate payments for review.

Add a column that flags any vendor paid the same amount more than once in the same month. Use a formula I can read, not a macro, and explain how it works.

What to check:

• Formulas: test them on rows where you know the answer, including blanks and zeros. The Excel formulas guide has a full test list.
• PivotTables and summaries: the grand total should equal the source total, or the trial balance figure it's meant to match.
• "Outliers" and "trends": open the underlying rows before you repeat the finding to anyone.
• Changes to the workbook: Copilot can edit the sheet. Work on a copy, or know how to get back to the earlier version.

In Outlook: long email threads

Copilot in Outlook can summarize an email thread from the top of the conversation (Microsoft). That's useful for catching up on a long client thread before a call, or pulling out the questions still open.

What to check: summaries leave things out. Before you act on one, confirm figures, dates and who agreed to what against the emails themselves. Don't treat the summary as the record, and don't forward it as one. If Copilot drafts a reply, check every figure, date and commitment in it as if a new staff member had written it.

In Teams: meeting recaps

In Teams meetings, Copilot can summarize the discussion, including who said what, and suggest action items. To ask Copilot about a meeting after it ends, the meeting needs to have been transcribed, and Copilot won't work in meetings hosted by another organization (Microsoft).

What to check: action items and owners against your own notes, and any figure said aloud. Numbers are easy to mishear in a transcript, and a recap can turn "we'll look into it" into a commitment. Follow your firm's policy on recording and transcribing client meetings.

Prompts that work well in Copilot

The habits that make any AI's work easy to check work in Copilot too: set the rules, point it at the evidence, ask it to show its working and cite where each figure came from. These three are a good start:

• "Use only the data in this workbook. If something isn't there, say so instead of assuming."
• "For each figure in your summary, tell me which sheet and cells it came from."
• "Summarize this thread as: decisions made, questions still open, and who owns each one. Quote the email each point comes from."

There are 12 more, each with what to check, in ChatGPT prompts for accountants. They work the same way in Copilot.

If your firm is rolling Copilot out

Plenty of finance teams have been told to use Copilot without being shown how. If you're the one setting it up, settle four things first:

1. Which version and plan. Confirm that everyone uses the work version, signed in with their work account, and which features your plan includes.
2. What can go in. Write down what client and company data is allowed, using the same three groups as for any AI tool: fine, anonymize first, never.
3. Who checks what. Decide which outputs need a second person before they reach the books or a client: formulas in shared workbooks, figures in client emails, meeting actions that commit the firm.
4. How people learn the checks. A short session on testing a formula, tying a total and reading a summary against its source does more than a list of prompts.

The rule that doesn't change

Copilot is convenient because it's already inside your files, email and meetings. That's also why its mistakes travel: a wrong figure in a summary or a recap is a short step from a client email. Treat everything it produces as a first draft, and check it before it goes into the books or out the door.