Use Copilot in Excel's chat mode to find which exhibit totals should tie

What This Does

Before a peer review, you check that the totals on a summary tab match the detail tabs behind them. Copilot's chat only mode reads the workbook and suggests which totals should tie and which ranges look out of line with their neighbors, without changing a cell. It gives you a checklist to confirm. It does not give you a verified answer.

Before You Start

• You have Excel for Microsoft 365 open on a workbook your company allows Copilot to read. Microsoft's page says Copilot in Excel is available on Windows, Mac, the web, iPad, iPhone and Android, with chat mode on all of them.
• Copilot is part of your license. Microsoft's page notes that Copilot may not appear if it is not included with your subscription or if your organization's settings turn it off. Look for the Copilot icon in the lower-right corner of Excel. If it is missing, ask your IT team which license you have. Pricing sits on Microsoft's own pricing pages.
• You know what your company's AI policy says about workbooks. In-force summaries, unfiled rates and client results go only into a tool the company has approved for that data. If you are unsure, use a copy of the workbook with invented values. The steps below work the same way.
• No policyholder, claimant or employee details are in the workbook. Use block or cell codes, not names, and delete any raw extract tabs from the copy.

Steps

1. Open Copilot and choose chat mode

Open the workbook and select the Copilot icon in the lower-right corner of Excel. Microsoft's page says Copilot opens in edit mode by default and offers three modes: edit, plan and chat. Switch to Chat only. The page says this mode analyzes your workbook data and gives insights without making changes to the workbook. Edit mode changes cells directly, so stay out of it for a checking task.

2. Ask which totals should tie

Type a prompt that names your tabs. Use the tab names exactly as they appear in your workbook.

On the Summary tab, list which totals should equal totals on the Data tab.
Then flag any cell range on the Data tab that looks inconsistent with its neighbors.
Do not recalculate anything. Only list what I should check.

Add a follow-up if the list is short: "Which Summary cells have no matching source on another tab?" Copilot should answer in the chat pane and leave the workbook alone. If a cell changes, press Undo and confirm you are in chat only mode.

3. Confirm every tie with your own formula

Treat the reply as a to-do list. For each pair Copilot names, write a check cell in a scratch area of the workbook, such as =Summary!C5-SUM(Data!C2:C4), and look for zero. Anything Copilot flags as inconsistent, open and read yourself. Copilot can miss a tie, invent one that does not exist, or misread a range. Your formula is the record. The reviewing actuary reads that, not the chat.

Real Example

Scenario: You are about to send a reserving exhibit to a peer reviewer. The Summary tab pulls totals from the Data tab. This workbook is invented, with codes and round numbers.

What you type: The prompt from step 2, with Summary and Data as the tab names.

What you get: A reply listing three pairs that should tie: earned premium, claim count and paid losses. It may also point at a range that looks odd next to its neighbors. You then run your own check cells:

• Earned premium: 400,000 + 350,000 + 250,000 = 1,000,000. The Summary shows 1,000,000. The difference is 0, so the tie holds.
• Claim count: 120 + 85 + 45 = 250. The Summary shows 250. The difference is 0, so the tie holds.
• Paid losses: 300,000 + 245,000 + 130,000 = 675,000. The Summary shows 665,000. The difference is 10,000, so the tie fails.

You trace the 10,000 to a Summary cell that points at an old range, fix the reference, and rerun the check. Copilot found the pair to check. Your formulas found the break.

Tips

• Never ask Copilot for the official figure or to "fix" a total. It lists what to check, and your own model and workbook produce the numbers.
• Name tabs and ranges in the prompt. A vague prompt returns vague checks, and a list of checks you already run is no gain.
• Keep your check cells in the workbook for the peer reviewer. The reviewer sees what you tested, which a chat reply cannot show.

Tool interfaces change. If a button has moved, look for similar Copilot or chat options in the same menu area.