Guide · October 22, 2026 · 5 min read

How to use AI in Excel (Copilot or a free chatbot)

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You probably don't need AI to "transform your data." You need the formula they can't remember, or a messy column fixed before a 2 p.m. meeting. AI is good at both. It can also hand you a formula that looks right and returns the wrong number, so checking gets its own section.

The Copilot details below come from Microsoft's own support and store pages, checked October 22, 2026.

Two ways to use AI in Excel

Copilot in Excel is built into the app. It reads your workbook and can change it directly, but it needs a paid plan or a work license.

A regular chatbot (ChatGPT, Claude, Gemini, or the free Copilot app) works alongside any version of Excel. It can't see your file. You describe your columns, it writes the formula, and you paste it in.

If you already pay for Microsoft 365, try Copilot first. If you don't, the chatbot route costs nothing and covers most formula questions. Not sure which chatbot? Our ChatGPT vs. Claude vs. Gemini vs. Copilot guide sorts that out.

Do you have Copilot in Excel? (plans as of Oct 2026)

Microsoft's Copilot in Excel FAQ says you need one of these:

• A Microsoft 365 Personal or Family subscription with an AI credits plan
• Microsoft 365 Premium
• A commercial Microsoft Copilot subscription
• A Copilot Chat-eligible Microsoft 365 or Office 365 business or enterprise subscription

US prices on Microsoft's store, as of Oct 2026:

On Family and Premium, Microsoft says the AI features are for the subscription owner only and can't be shared. At work, ask IT before buying anything yourself.

Two requirements trip people up. Copilot in Excel needs AutoSave turned on, which Microsoft says means the file has to be saved to OneDrive. And Copilot can only edit when Calculation Options are set to Automatic.

How to use Copilot in Excel

1. Save the file to OneDrive and make sure AutoSave is on.
2. Turn your data into a table. Select it, then Home → Format as Table. Microsoft says a plain range also works if it has one header row, unique headers with no blanks, no merged cells, no subtotals, no empty rows or columns, and consistent formatting.
3. Select the Copilot icon in the lower-right corner of Excel.
4. Pick a mode. Edit mode (the default) changes your workbook directly. Plan mode shows you a plan to approve first. Chat mode answers questions without touching the file.
5. Ask in plain English.

I'd start in plan or chat mode until you trust it. All three modes work on Windows, Mac, and the web. On iPhone and Android it's chat mode for now (iPad gets chat and plan), and Microsoft says edit mode is rolling out to iPad and iPhone.

A prompt to try:

Add a column that shows each order's profit (Revenue minus Cost)
as a percentage of Revenue. Explain the formula you used.

One change to know about: Microsoft retired the =COPILOT() function, a preview feature that ran AI inside a cell, on September 14, 2026. Old results stay as cached values, but cells that recalculate show #NAME?. Tutorials that still teach it are out of date.

How to use a free chatbot for Excel formulas

The trick is describing your sheet without pasting your data. Column letters and headers are almost always enough.

I'm using Microsoft Excel. My data is on Sheet1:
- Column A: Order date
- Column B: Region (text, like "East")
- Column C: Sale amount (number)
Headers are in row 1. Data runs from row 2 to row 500.

Write a formula for cell G2 that [describe what you want, e.g.
"adds up sales for the region typed in F2, for 2026 orders only"].
Then:
1. Explain in plain English what each part does.
2. Tell me what could make it return a wrong answer.
3. Give me 3 test rows I can type in to check it by hand.

Points 2 and 3 matter most. You see the weak spots before anyone else does.

When a formula throws an error, paste it back with the exact error (#N/A, #VALUE!) and a line about what's in the column it uses. Ask what's likely wrong and how to fix it.

Check every formula before you trust it

Microsoft's own FAQ says Copilot "can sometimes make mistakes, misinterpret information, or produce inaccurate results." Chatbots can too. Here's the routine I'd use:

• Test five rows by hand. Pick ones you can do in your head and compare.
• Step through it. On the Formulas tab, in the Formula Auditing group, select Evaluate Formula, then Evaluate. You'll see each piece calculate in order.
• Try the awkward cases. Blank cells, text where a number should be, and dates typed as text are the ones I'd test first.
• Keep a copy before edit mode. Microsoft says you can undo Copilot's changes or view prior versions, and that once changes are saved, anyone with access to the file sees them, including coauthors.

Microsoft also says to avoid using Copilot for decisions in sensitive areas like finance, legal, or medical topics.

What not to paste

The rule on this site: if you wouldn't email it to a stranger, don't paste it into a free AI tool. Spreadsheets are where this goes wrong fastest, because one paste can hold hundreds of customer names, salaries, or account numbers. With a chatbot, describe the columns and use made-up sample rows. Issue #1 covers the training settings for each chatbot.

Copilot in Excel reads the file you're working in. For personal Microsoft accounts, Microsoft says prompts, responses, and file contents in Copilot in Microsoft 365 apps aren't used to train foundation models. That's not permission to use a personal account for work files. At work, your company's policy and its approved tool win.

Try it today

Pick the one formula you look up every month. Describe it with the chatbot prompt above (or ask Copilot), test it on five rows, and save the prompt that worked. If you're still deciding whether a paid chatbot is worth it, Free ChatGPT vs. Plus covers that.

Sources

All checked October 22, 2026. Prices are US and exclude tax.

• Microsoft Support, Get started with Copilot in Excel (what it does, the Copilot icon, edit/plan/chat modes, platforms)
• Microsoft Support, Frequently asked questions about Copilot in Excel (eligible plans, limitations, Automatic calculation, undo and prior versions)
• Microsoft Support, Format data for Copilot in Excel (table and range rules, AutoSave)
• Microsoft Support, COPILOT function (retired September 14, 2026)
• Microsoft Support, Evaluate a nested formula one step at a time
• Microsoft Support, Copilot in Microsoft 365 apps for home: your data and privacy
• Microsoft Store, Microsoft 365 plans and prices (monthly and yearly prices) and Compare Microsoft 365 plans (Copilot in Excel usage levels, owner-only AI, AutoSave and OneDrive requirement)