“I heard Excel added something called the COPILOT function, but when I try it in my Excel, I just get an error...”

The COPILOT function has been making the rounds on social media. It sounds almost too good to be true: AI directly inside your spreadsheet cells. But the requirements for using it are actually pretty strict.

In this article, we'll break down the COPILOT function's requirements, pricing, use cases, and things you shouldn't use it for as of March 2026. Whether you're wondering “Why can't I use it?” or “What do I need to try it?”, this guide should help.

What is the COPILOT function? How is it different from regular Excel functions?

The COPILOT function is a new Excel function Microsoft announced in late 2024. In simple terms, it's a function that lets you call AI, or a large language model, from inside a cell to process text.

For example, you can use it like this.

=COPILOT("このレビューをポジティブかネガティブに分類して", A2)

Traditional functions like SUM and VLOOKUP calculate things based on fixed rules. The COPILOT function is a completely different type of function: you ask AI a question and get an answer back.

The syntax looks like this.

=COPILOT(プロンプト, [参照1], [プロンプト続き], [参照2], ...)

You put your instruction to the AI, or prompt, in the first argument, then pass cell ranges as references in the later arguments. Because you can alternate multiple prompts and references, you can write more complex instructions in a single function, such as “Look at the product names in column A, use the descriptions in column B, and classify them into the categories in column C.”

Why so many people can't use it: the requirements are strict

There are lots of posts on social media from people saying, “When I type =COPILOT( in Excel, I just get an error!” And that makes sense, because you need to meet all three requirements to use the COPILOT function.

Requirement 1: You need a Microsoft 365 Copilot license

The COPILOT function is treated as a “premium Copilot feature.” In other words, a regular Microsoft 365 subscription isn't enough.

As of March 2026, the additional license and pricing are as follows.

  • Business users: Microsoft 365 Copilot — 4,497 yen per user/month with an annual contract
  • Personal users: Copilot Pro-equivalent features included with Microsoft 365 Personal / Family are required

In short, it's not free. Even if your company already has Microsoft 365, you won't be able to use it unless you also have a separate Copilot license.

Requirement 2: You need to be on the Beta Channel or a preview channel

As of March 2026, the COPILOT function still hasn't reached general availability. To use it, you need to be in one of the following channels.

  • Beta Channel via the Microsoft 365 Insider Program
  • Current Channel (Preview) via the Frontier Program

These channels let you try new features early, but they can also be unstable. The function isn't available yet in the standard “Current Channel” or “Monthly Enterprise Channel.”

Requirement 3: You need a supported platform

The COPILOT function works in the following environments.

  • Excel for Microsoft 365 on Windows
  • Excel for Microsoft 365 on Mac
  • Excel for the web
  • Excel for iPhone

That said, according to Microsoft's official support page, availability varies by channel and version, so you may still be unable to use it even in one of the environments listed above.

What the COPILOT function is good at, and what it isn't

The COPILOT function isn't a magic wand. It has clear strengths and weaknesses, and using it for the wrong kind of task can cause real trouble.

What it's good at

  • Classifying and tagging text: Sorting reviews into positive/negative, categorizing support inquiries, and so on
  • Summarizing text: Turning long descriptions into one-line summaries
  • Generating sample data: Creating dummy data for testing
  • Translating and rephrasing: Converting English product names into Japanese, for example
  • Extracting data: Pulling dates, amounts, and similar details out of freeform text

What it's bad at, and where you shouldn't use it

This part is extremely important. Microsoft officially warns users not to use it for tasks that require accuracy or repeatability.

  • Numerical calculations: Use traditional functions like SUM and AVERAGE for totals, averages, and aggregation
  • Financial reports and legal documents: Don't use it in situations where a wrong number could create a serious problem
  • Getting up-to-date information: The AI's knowledge is limited to information from around June 2024
  • Cases where you need the exact same result every time: The same prompt can return slightly different results from one run to the next

An Office Watch test article reported cases where the COPILOT function omitted data or returned answers that didn't match the facts. In other words, AI can give you an answer that sounds right but is still wrong.

Watch out for usage limits and rate limits

There's one more easy-to-miss limitation with the COPILOT function: usage caps.

  • Up to 100 calls per 10 minutes
  • Up to 300 calls per hour

For example, if you autofill the COPILOT function across 1,000 rows of data all at once, you'll hit the limit partway through and get a “#CONNECT!” error.

If you want to process a large dataset, you'll need to do it in batches of a few hundred rows or wait a while before running it again. It's a small detail that can get frustrating fast, so it's worth knowing ahead of time.

How is it different from the ChatGPT for Excel add-in?

You might be thinking, “Wait, wasn't there something called ChatGPT for Excel too?” There is, but the two are completely different.

ItemCOPILOT functionChatGPT for Excel add-in
ProviderMicrosoftOpenAI
CostMicrosoft 365 Copilot license, from 4,497 yen/monthChatGPT Plus, about 3,000 yen/month
How it worksBuilt-in Excel functionAdded as an add-in
AI modelMicrosoft models on AzureOpenAI GPT models
Data handlingProcessed within Microsoft's security policiesSent to OpenAI's servers
Official release statusStill in preview as of March 2026Released in 2025

If you're using it at work, where your data is sent is a major security consideration. Because the COPILOT function is processed inside Microsoft's cloud, companies already using Microsoft 365 for business may find it easier to adopt.

What to prepare even if you can't use it yet

You might be tempted to think, “If it's still in preview, this doesn't matter yet.” But there are a few things you can do now to get ready for the full release.

  1. Format your data as a table: The COPILOT function works well with table-formatted data. Convert your data to a table with Ctrl+T
  2. Make column headers clear: Instead of labels like “A” and “B,” use meaningful headers like “Product Name” and “Review” to help improve AI accuracy
  3. Keep using traditional functions well: The COPILOT function isn't good at numerical calculations, so basics like SUM, IF, and VLOOKUP will still be essential
  4. Ask your company's IT department about Copilot licensing plans: For business users, an admin has to assign the license, so you can't simply start using it on your own

FAQ

Can I use the COPILOT function for free?

No. You need a premium Microsoft 365 Copilot license. For business users, it costs 4,497 yen per user/month with an annual contract as of March 2026. A regular Microsoft 365 subscription alone isn't enough.

Can the COPILOT function calculate sums and averages?

Technically, yes, but Microsoft explicitly says to use traditional functions like SUM and AVERAGE for numerical calculations. The COPILOT function can make calculation errors, so don't use it when accuracy matters.

Can I use Japanese prompts?

Yes. Japanese prompts are supported. You can give instructions in Japanese, such as “Summarize this text” or “Classify this as positive or negative.”

Will the COPILOT function return the same result every time?

No. Because it's AI-based, the same prompt can return slightly different results each time it's run. For work that requires repeatability, it's a good idea to copy the results and use “Paste Values” to lock them in.

Which is better: the ChatGPT for Excel add-in or the COPILOT function?

It depends on your use case and environment. If you're handling company data, the COPILOT function may feel safer because it's processed within Microsoft's security policies. If you're using it personally and want something easier to try right away, the ChatGPT for Excel add-in, which has already been officially released, may be the better starting point.

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