How to Use Copilot in Excel (and Fix a Greyed-Out Button)

Copilot in Excel lets you ask for formulas, charts and summaries in plain English instead of hunting through menus. It's handy for people who use spreadsheets but don't live in them. It's also fussy about where your file is saved, which is why so many people open Excel, can't find the button, or see it greyed out. Here's how to set it up and get useful answers from it.

Before you start: the three requirements

Requirement	Why it matters
A Microsoft 365 plan with Copilot	The button won't work without it
File saved to OneDrive or SharePoint	Copilot works with cloud workbooks
A modern file type: .xlsx, .xlsb or .xlsm	Older and Strict Open XML files aren't supported

Microsoft's simplest advice is to save to OneDrive and leave AutoSave on. If your file is an old .xls or saved only on your computer, use File, Save As, choose OneDrive and pick the Excel Workbook format.

Open Copilot in Excel

1. Open the workbook from OneDrive or SharePoint.
2. On the Home tab, select Copilot at the right of the ribbon.
3. The Copilot pane opens on the right. Type a request, or pick a suggested prompt.
4. Review what Copilot proposes, then choose to insert it or try again.

Microsoft is also rolling out a small Copilot button anchored in the corner of the document, so if you can't see it on the ribbon, look there.

Things to ask Copilot in Excel

• "Add a column that calculates the total for each row."
• "Highlight any order above the average in red."
• "Show me a chart of sales by month."
• "Summarise the key trends in this data."
• "Sort this table by date, newest first."
• "Explain what this formula does."

Be specific about column names and what you want, and Copilot does much better. Ask one thing at a time rather than five. If the first answer misses, rephrase with more detail, such as which column to use and where to put the result, rather than starting again from scratch.

Starting from a blank sheet

You don't need data first. Microsoft notes Copilot doesn't require existing data, so you can ask it to build something, such as a simple project tracker with columns for task, owner, due date and status, and then fill it in yourself.

Format your data as a table first

Copilot works best when your data is tidy. Select your data, press Ctrl and T, and confirm it has headers. Clear headers like Date, Customer and Amount help Copilot understand what each column is. Remove blank rows and merged cells, which confuse it. If you want Copilot to pull data in from another Excel file, Microsoft says that only works from files whose data is in tables.

Always check the answer

Copilot is quick but not infallible. Click into any formula it adds and read it. Spot-check a few totals by hand, especially before the numbers go in a report or to a client. Copilot can misread a column or include a total row twice, and a wrong number that looks confident is worse than no number.

Why Copilot is greyed out or missing

• The file is saved locally rather than in OneDrive or SharePoint.
• It's an older file format; save it as .xlsx.
• Your Microsoft 365 plan doesn't include Copilot, or your organisation hasn't assigned it to you.
• You're signed in with a different account from the one with Copilot.
• Your Excel needs updating: File, Account, Update Options.

Undo what Copilot changed

When Copilot adds a column, formats cells or sorts data, it changes your workbook straight away. If you don't like the result, press Ctrl and Z to undo, just as you would after your own edit. Because AutoSave is on, it's worth making a copy of an important workbook before you let Copilot loose on it: File, Save a Copy. Then you can experiment without worrying about the original, and compare the two afterwards.

Copilot in Excel on the web and Mac

Copilot also appears in Excel for the web at office.com and in Excel for Mac, in the same place on the Home tab. The requirements are the same: a cloud-saved file and a plan that includes Copilot. Some newer features reach Windows first, so if a Microsoft guide mentions something you can't see on a Mac, that's often why.

For the bigger picture on what Microsoft's assistant can do across Office, see my explainer what is Microsoft 365 Copilot. And if you'd like to compare it with another AI that works with spreadsheets, my guide to Claude for Excel shows a different approach.

My verdict

Save the workbook to OneDrive, open Copilot from the Home tab and ask for one specific thing at a time, using your column names. Turn your data into a table first, and check every formula Copilot adds before trusting the totals. If the button is greyed out, the file location or format is the usual cause, not Copilot itself.

Frequently asked questions

How do I use Copilot in Excel?

Save the file to OneDrive or SharePoint, select Copilot on the Home tab and type what you want.

Why is Copilot greyed out in Excel?

Usually the file isn't saved to OneDrive or SharePoint, or it's an older file type.

Which file types does Copilot in Excel support?

Workbooks saved as .xlsx, .xlsb or .xlsm.

Does Copilot in Excel need data in a table?

It works best with tables, and importing from another file needs them.

Can Copilot in Excel start from a blank workbook?

Yes. It doesn't need existing data.

Is Copilot in Excel always accurate?

No. Check formulas and totals before you rely on them.