COPILOT

What it does

COPILOT(prompt_part1, [context1], [prompt_part2], [context2], ...)

COPILOT sent a prompt and optional cell data to an AI model and returned its reply in the sheet. Microsoft withdrew it: its page says that from 14 September 2026 the function is no longer available in Excel, and points to Copilot in Excel, opened from the Copilot icon, instead.

COPILOT(prompt_part1, [context1], [prompt_part2], [context2], ...)

• prompt_part is text describing the task.
• context is a cell or range that supplies data.

Prompt parts and context arguments alternate, so a formula can place data between pieces of a prompt:

=COPILOT("Classify sentiment",B2:B100)

Try it

DNA Calc does not run this function yet: its answer needs an outside service. In Excel you would write:

=COPILOT("Describe these values",B2:B4)

Quirks

• It was never a fixed mapping. The model behind it could change, so one formula could give different results at different times. This handbook's method of comparing recorded answers does not apply to such a function.
• Rate limits. Microsoft's announcement gave 100 calls every 10 minutes and up to 300 an hour. One call with a large array counted once; filling across cells counted each cell.
• It was a preview. It was offered through Microsoft's Frontier and Insider programs.

When the service is unavailable

Microsoft's page describes the withdrawal itself. Results already calculated stay in workbooks as cached values. Once such a cell recalculates, it shows #NAME?, because Excel no longer knows the function. So a workbook can look intact until a recalculation reaches it.

How to implement

DNA Calc does not run this function yet, and it is deferred by policy: the answer depends on a back end Microsoft hosted and controlled, and has since withdrawn. Reading a file that uses it is still worth doing correctly:

1. Keep the cached value on load, as Excel does, and do not recalculate it silently.
2. Give #NAME? on recalculation, which is Excel's documented outcome since the withdrawal.
3. Offer the formula text so a user can replace the call.

A new function with this shape would need an AI service, rate limiting, asynchronous calculation and a result whose shape can change. It would not be this function.

Rust code

This entry has no Rust implementation yet.

No implementation has been published with a Handbook test suite for this function.

Version differences

Microsoft's page lists Excel for Microsoft 365 on Windows and Mac, the web app and Excel for iPhone, before the withdrawal of 14 September 2026. No Excel answers for this function are recorded here, so no comparison between Excel builds exists.

Alternatives

• Copilot in Excel, the replacement Microsoft names.
• TRANSLATE and DETECTLANGUAGE for those two tasks.
• Paste a useful result as values, so it survives recalculation.

Named variants

No named variants are recorded yet.