Copilot Excel Formulas: Ask in Plain English, Then Run These 4 Checks
The short answer: describe the result you want in plain English, pick the right route, and check the formula before you trust it. Same calculation down a whole table? Ask for a column. Need 1 answer? Ask for a single-cell formula. Inherited a formula? Ask Copilot to explain it. Then run 4 checks: read the formula, test 3 rows by hand, test the edge cases, and ask what else changed.
Microsoft publishes example prompts for the first 3 routes. A prompt with IF in it? None turned up on the Microsoft pages checked for this article, so my IF examples below are labelled as mine. (Looking for the =COPILOT function? It was retired on 14 September 2026. That story has its own page: Excel's COPILOT function is gone.)
Which route? Pick before you type
Choose the route first, because the wording of the prompt follows from it.
1Formula column or row
If you want the same calculation on every row, or a total row, then ask for a column or a row. Lookups live here too. Microsoft says Copilot recommends a formula such as XLOOKUP and adds a new column for the results.
2Single-cell formula
If you need one answer, then name the cells you mean and say what to calculate.
3Explain
If you didn't write the formula, then select its cell and ask. Asking for an explanation edits nothing. Chat mode makes no changes to your workbook, so asking there leaves the file alone. Microsoft documents the request but doesn't name a mode for it.
4Fix
If a formula returns an error value, then there is no documented route. Microsoft's current pages describe no fix with Copilot feature. Section 05 below says what to do instead.
Copilot Excel formula prompts, straight from Microsoft
These come straight from Microsoft's own page on getting insights with Copilot in Excel. I'm showing them exactly as written, so you can copy the pattern onto your own columns.
A setup line first: Copilot editing only works when Calculation Options are set to Automatic. Check that before anything else.
Add a column that calculates the profit margin for each product.
Add a column that shows each region's percentage of total sales.
Add a row that calculates the average revenue, ROI, and sales.
Calculate the percentage increase from cell A1 to cell B1.
Extract the first name from a full name in cell C1.
Create a column that looks up the quantity in stock for each item from the inventory sheet.
Explain the formula in cell D3.
Notice what they share? Each one names what to calculate and where. Microsoft's tip says the same: name the columns or ranges you want Copilot to work with.
Want totals by category instead of a formula column? That's a job for a PivotTable, and this page covers it.
Copilot Excel formula with IF: my examples, not Microsoft's
No official Microsoft Copilot prompt with IF turned up in the pages checked, so I wrote these 2. They follow the same pattern as Microsoft's. Treat them as a starting point.
Add a column that shows Late if the date in column C is before today and the status in column D is not Done, otherwise show OK.
Add a column that shows High if the amount in column E is above 10,000, Medium if it is above 1,000, and Low otherwise.
Here's the catch: a plain-English rule can become a formula in more than one way. That's why the next section exists.
The 4 checks before you trust a Copilot formula
Good news first. Microsoft says Copilot updates your workbook using Excel's built-in features, and your content stays editable. That's what makes these checks possible. The formula is right there for you to read.
Now some cold water, courtesy of Microsoft. For finance files, Microsoft also tells people to avoid Copilot for decisions in sensitive areas, finance among them. So run the checks every time.
1Read the formula, not the result
Click a result cell and look at the formula bar. Do the references point at the columns you meant?
2Test 3 rows by hand
The first row, the last row and 1 odd one. Use a calculator, not Copilot.
3Test the edges
Blanks. Zeros. Text that looks like a number. Lookup keys that differ by a single space. Those are the places where a formula that looks right gives a wrong answer.
4Ask what else changed
In edit mode Copilot changes the workbook directly, and co-authors see saved changes. So ask what it touched. Microsoft's screen-reader tutorial suggests this prompt:
List every cell, range, and sheet you just modified, and what you changed in each one.
Microsoft says you can undo changes or view prior versions, and its tutorial suggests working in a copy when the stakes are high. (I have no commercial interest in Microsoft. I just like backups.)
Got an error value? What Microsoft documents and what it doesn't
Short version: Microsoft's current support pages for Copilot in Excel describe no fix with Copilot feature for #N/A, #REF! or #VALUE!, and no button for it. Microsoft's #N/A example prompt does exist, but it sits in a November 2024 blog post, written for the older Copilot chat, before edit, plan and chat modes existed.
So I won't tell you Copilot fixes errors. Here is what to do instead (my method, not Microsoft's): ask it to explain the formula, find the broken reference yourself, change it, then run the 4 checks. (Microsoft's error pages do show a Get help with Copilot box. Tempting, I know. It's a help widget on a web page, not an action inside Excel.)
Explain the formula in cell F8 and tell me which part could return an error.
A formula someone else wrote?
Inherited formulas are like inherited furniture: nobody remembers why it's there, and nobody wants to move it. Select the cell, ask Copilot to explain it, then compare its explanation with the cells it names. That's the whole trick. Really. For a whole inherited file, with 7 questions to ask before the meeting, see Got a spreadsheet you didn't build?.
Questions about Copilot Excel formulas
How do I write a formula with Copilot in Excel?
Select the Copilot icon in the lower-right corner of Excel (F6 moves focus to it), describe the result in plain English, and name the columns or cells. Ask for a column, a row or a single-cell formula. Then read the formula before you trust it.
Can Copilot write an IF formula in Excel?
Microsoft lists generating formulas as something Copilot does, but the example prompts on its insights page include none with IF. So describe the rule, ask for a column, and test it with the 4 checks.
Can Copilot do XLOOKUP or VLOOKUP in Excel?
Microsoft says Copilot can look up values from elsewhere in your workbook and recommends a formula such as XLOOKUP in a new column. VLOOKUP? Its insights page names no other lookup function.
Can Copilot explain a formula in Excel?
Yes. Select the cell and ask something like Explain the formula in cell D3. Microsoft documents this as a way to understand inherited formulas.
Can Copilot fix formula errors in Excel?
Microsoft documents no fix with Copilot feature for error values. Ask Copilot to explain the formula, then make the change yourself and check it.
Why won't Copilot edit my formulas?
Start with Calculation Options, because Copilot editing only works when they're set to Automatic. Already set? Microsoft lists 2 more causes: the file is checked out in SharePoint, or it's saved as Strict Open XML. For Strict Open XML, save a copy as .xlsx.
Formulas get checked by people. Practise the checks.
I run live online Copilot workshops, hands-on, from 1.5 to 4 hours, for groups of 20 to 25 at most. Teams that live in Excel have their own session. Clients include Intel, Roche, EY and Amdocs.