Get Excel totals you can trust after Copilot cleans your data
It explains each hidden problem and why it would throw off a formula, then lets you pick which fixes go in.
Published . Steps as of October 2026.
Why are my Excel totals wrong and how do I fix them?
Run the clean data skill in Copilot in Excel by typing @clean-data or picking it from the Skills menu. It finds issues like extra spaces, mixed dates, duplicates and numbers stored as text, then proposes fixes you choose. As of October 2026, it's rolling out on Excel for Windows, Mac and the web. If you have one small list, a single check is enough. If you build reports from the sheet, run it before every PivotTable.
A sketch of what you'll get back.
Your prompt
Fill in your details. Skip any you like.
This AI can't be filled in from a link, so the button copies your prompt: paste it into the new chat.
The prompt that gets copied
@clean-data Check the [SHEET NAME, e.g. 2026 Invoices] sheet before I build totals and a PivotTable from it. Look for anything that would make sums, lookups or counts wrong: extra spaces, names spelled two ways, dates in mixed formats, duplicate rows and numbers stored as text. The columns I care about most are [KEY COLUMNS, e.g. Client, Date, Amount]. Treat [WHAT COUNTS AS DUPLICATE, e.g. same client, date and amount] as a duplicate. For each problem, tell me in plain words how many rows it affects and what it would have thrown off. Propose fixes, but don't apply anything until I choose.
Ask Copilot in Excel to check your sheet for hidden problems like extra spaces, mixed date formats, duplicates and numbers stored as text, then pick which fixes to apply before you total anything.
Step by step
- Open the workbook with your sales, client or invoice list in Excel
- Open Copilot and type @clean-data, or pick it from the Skills menu
- Paste the prompt and name the sheet and columns that matter
- Review the proposed fixes and apply only the ones you agree with
What you'll get
A plain-words list of the hidden problems in your sheet, how many rows each affects, and proposed fixes you approve one by one.
Needs Copilot in Excel. The clean data skill is rolling out on Excel for Windows, Mac and web as of 2026-10-27.
- Made for
- Small business owners, Consultants, Coaches
- Works in
- Copilot
