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 had planned general availability for 2027 but updated its roadmap in June 2025 to say it will not move forward with the feature.
• Users can still access the same AI capabilities, including data summaries and content generation, through the Copilot side pane inside Excel.
• 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, the function will simply stop working.

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

The COPILOT() function, introduced in August 2025 for preview users, let you type an instruction inside a spreadsheet cell and get a response from Microsoft's AI assistant, Copilot, right there on the sheet. Think of it as asking ChatGPT a question, but doing it from inside your budget spreadsheet rather than from a separate app.

Microsoft told customers in its 365 Message Centre that pulling the feature "helps streamline the Copilot experience within Excel." In plain terms: the company decided one AI entry point, 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, first reported by The Register AI, is blunt: "We have decided not to move forward with this feature. We apologise for the inconvenience."

Microsoft had planned to make COPILOT() broadly available in 2027. That plan is now cancelled.

Should anyone who used it be worried?

No one should be in crisis, but some people do have work to do.

Because the function stayed in preview throughout its life, Microsoft's own guidance said users should not rely on it for real business workflows. Anyone who did use it in a live spreadsheet will need to rewrite those cells before September next year.

For everyday tasks such as summarising a column of text, categorising entries, or pulling information together, the Copilot side pane covers the same ground. The side pane 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. Google announced an AI cell function for Sheets in June 2025, and it remains available.

Microsoft, for its part, has spent recent months trying to make Copilot behave more consistently across Word, Excel and Outlook. Small user-experience tweaks, such as letting people move the floating AI action button to the toolbar instead of leaving it hovering over their content, suggest the company is listening to complaints about the feature feeling intrusive.

Dropping a worksheet function that duplicated what the side pane already did fits that pattern. Fewer AI entry points means fewer places for things to go wrong.

If you are a heavy Excel user and this change affects your workflow, the practical step is straightforward: 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.