Microsoft’s latest Excel update introduces the COPILOT function, a new AI-powered formula that allows users to analyze, summarize, and generate content directly inside their spreadsheets using natural language prompts. This function is now rolling out to Beta Channel users on Windows and Mac with a Microsoft 365 Copilot license, marking a significant shift in how people can interact with spreadsheet data. However, Microsoft is upfront about its limitations: the AI is not designed for tasks where precision or repeatability are critical.

How the COPILOT Function Works

The COPILOT function brings large language model capabilities right into the Excel grid. Instead of writing complex formulas or scripts, users can type a natural language request and reference cell ranges as context. For example, to classify customer feedback by sentiment, you might enter:

=COPILOT("Classify this feedback", D4:D18)

The AI then processes the specified range and generates results—such as sentiment tags or summaries—directly in the spreadsheet. The function’s syntax allows multiple prompt and context pairs, making it flexible for a range of text-based tasks.

Unlike add-ins or external scripts, COPILOT is integrated with Excel’s calculation engine. This means outputs automatically update when the referenced data changes, streamlining workflows that previously required manual refreshes or rerunning scripts.

What You Can (and Can’t) Do With COPILOT

Microsoft’s documentation and blog posts highlight several practical uses for COPILOT:

  • Summarizing large blocks of feedback or text for quick overviews.
  • Classifying data, such as sorting survey responses or support tickets by topic or sentiment.
  • Generating lists or tables from prompts, like creating SEO keyword ideas or drafting outlines.
  • Brainstorming or rewording content in different tones or styles.

However, there are important restrictions. Microsoft explicitly warns users not to rely on COPILOT for numerical calculations, financial reporting, legal documents, or any scenario where accuracy and reproducibility are essential. The AI can produce incorrect or inconsistent results, a known limitation of large language models. For example, using COPILOT to sum numbers or perform regulatory calculations risks introducing errors that could go unnoticed.

Additionally, COPILOT currently cannot access live web data or internal business documents. All prompts are limited to the data present in the workbook, and the function is capped at 100 calls every 10 minutes (or 300 per hour). Microsoft states that user data sent through COPILOT is not used to train its models and remains confidential.

Integrating COPILOT With Traditional Excel Functions

One of COPILOT’s strengths is its ability to work alongside standard Excel formulas. Users can nest COPILOT inside functions like IF, SWITCH, or LAMBDA, or use the output of other formulas as input for AI prompts. This approach allows for more dynamic and context-sensitive analysis without overhauling existing spreadsheet structures.

For instance, you could use COPILOT to generate a plain-language summary of a calculated result, or to categorize text data that’s been pre-processed by other formulas. The function is entirely optional and only appears in worksheets where it’s specifically used.

Best Practices and Limitations

Writing clear, specific prompts is crucial for getting useful results from COPILOT. Microsoft recommends explicitly stating which cells to include, the desired output format (such as a table with headers), and using action verbs like “summarize,” “categorize,” or “rank.” If the AI returns unexpected or irrelevant results, refining your prompt or providing examples can improve accuracy.

Despite its convenience, COPILOT’s AI is not infallible. It may misunderstand ambiguous prompts, “hallucinate” plausible-sounding but incorrect answers, or fail to follow instructions precisely. For critical business applications, Microsoft urges users to review and validate all AI-generated outputs before using them in reports or decisions.

Currently, the function also lacks support for some Excel-specific data types. For example, dates returned by COPILOT are formatted as text, not as Excel’s native date serial numbers, which can affect downstream calculations.

What’s Next for AI in Excel?

Microsoft is actively developing COPILOT, with plans to expand its capabilities. Upcoming improvements may include better support for large data arrays, enhanced model performance, and future access to web and enterprise data. Feedback from beta users will help shape how the feature evolves, but for now, its most reliable use cases are in text analysis, brainstorming, and content generation rather than numerical computation.

Microsoft’s COPILOT function in Excel introduces powerful new ways to work with text data, but it’s not a replacement for traditional formulas when accuracy matters. For now, it’s best viewed as a creative assistant for summaries and ideas—not as a tool for mission-critical calculations.