Microsoft is killing its Excel Copilot formula after less than a year

Key points

• Microsoft will retire the COPILOT() worksheet function in Excel on 14 September 2026, less than a year after its August 2025 preview debut.
• The feature never left preview and was never included in a standard Microsoft 365 subscription without a separate Copilot licence.
• Microsoft updated its roadmap in June 2025 to cancel the feature, dropping earlier plans for a 2027 general release.
• Users can still access AI assistance through the Copilot side pane inside Excel, which covers summarising data and generating content.
• Google Sheets launched a comparable AI cell function in June 2025 and has not announced plans to remove it.

If you built any spreadsheet formulas around Microsoft's COPILOT() function, you have until 14 September 2026 to replace them. After that date, it simply stops working.

What was this function, and why is Microsoft dropping it?

Introduced in August 2025 for Beta Channel preview users, the COPILOT() function let you type an instruction inside a spreadsheet cell and get a response from Microsoft's AI assistant right there on the sheet. Think of it as prompting an AI from inside your budget spreadsheet rather than switching to a separate app.

Microsoft's 365 Message Centre said the change "helps streamline the Copilot experience within Excel" while keeping AI available through a supported interface. In plain terms: the company decided the Copilot side pane (a panel that slides out from the edge of the screen) is enough.

The update to Microsoft's public product roadmap is blunt: "We have decided not to move forward with this feature. We apologize for the inconvenience." That's the whole explanation. Microsoft had planned a 2027 general release, and that plan is cancelled.

This fits a pattern we've been tracking. As we reported on 13 August, Microsoft is already merging its two Copilot apps into one, with some features not surviving the move. Killing a duplicated worksheet function reads like the same instinct: fewer entry points, less to maintain.

Should anyone who used it be worried?

Not panicked, but some people do have work to do.

Because the function stayed in preview throughout its life, Microsoft's own guidance said users shouldn't rely on it for real business workflows. Anyone who ignored that and built it into a live spreadsheet now needs to rewrite those cells before next September.

For everyday tasks like summarising a column or categorising entries, the Copilot side pane covers the same ground. It requires a Microsoft 365 Copilot licence, a paid add-on that costs extra on top of a standard Microsoft 365 subscription.

What does this mean for people who like the idea of AI in spreadsheets?

Google Sheets still offers something similar, having announced its AI cell function in June 2025 with no retirement notice since.

Microsoft, meanwhile, has spent recent months consolidating Copilot. Small adjustments, like letting users move the floating AI action button to the toolbar instead of leaving it hovering over their content, suggest the company is responding to complaints about the feature feeling intrusive. Dropping a worksheet function that duplicated what the side pane already did fits that same logic. Fewer AI entry points means fewer places for things to break.

If this change affects your workflow, the practical step is simple: open the Copilot side pane, try the same tasks there, and confirm they work the way you need before next September.

Common questions

Do I need a special licence to use Copilot in Excel after September 2026?

Yes. Copilot in Excel, whether through the side pane or the now-cancelled cell function, requires a Microsoft 365 Copilot licence, which is a paid add-on separate from a standard Microsoft 365 subscription.

Will Google Sheets still have an AI cell function?

As of June 2025, Google Sheets offers a comparable AI function and has made no announcement about removing it.