Microsoft is promoting Excel Agent as a powerful new AI feature designed to build entire worksheets from a single prompt—but how well does it actually work? Office Watch put Excel Agent to the test and found a mix of promise and pitfalls. From creating a mortgage comparison sheet to handling complex formulas, Excel Agent shows potential but also stumbles with slow performance, unexplained errors, and inconsistent results. Here’s what you need to know before relying on Excel’s newest AI tool.
Close but no Cigar
We tried a variation on Microsoft’s example and you can see the (mixed) results below but in short …
By all means try out the Excel Agent but be VERY careful, check the AI work and don’t expect too much.
This is a preview or Frontier project but even so, Microsoft should have this tool working more reliably before promoting it so heavily.
As happens too often with Copilot, the initial public release doesn’t match Microsoft’s hype.
It gives the appearance of being released to the public by some marketing calendar or PR need rather than first evaluating the quality of the product.
Mortgage Comparison
Instead of simple monthly payments (Microsoft’s Agent example), we asked to compare monthly vs four-weekly payments. Making four-weekly payments is a relatively painless way to greatly shorten a mortgage and interest paid.
Here’s the prompt we used:
“Build a mortgage calculator that compares the same regular fixed payment made monthly vs payment every 4 weeks, based on user inputs for loan amount, annual interest rate, maximum term in years and payment amount. Generate a schedule showing month, payment, principal, interest, and remaining balance. Present the results in a clear, formatted table.”
The sheet is made before your eyes (or while you’re getting another coffee).
It took almost 15 minutes to make the complete mortgage comparison sheet with, as we’ll see, plenty of #VALUE errors.
The Agent side-pane goes into a lot of detail about what it did under headings like:
- What I built & assumptions
- How the calculations work (formulas explained)
- Verification (with default inputs)
- Edge cases & tips
- What I fixed during setup
- Completeness confirmation
And finally offering to make some commonly needed changes
- Would you like any refinements?
Tip: copy all the Excel Agent commentary into a Word document or OneNote page for future reference. It’s a good explanation of the sheet and it’s formulas.
The Agent made sheet has data entry cells (blue colored) and a summary plus a ‘per payment’ schedule showing the amount of principal and interest plus balance (in theory).
Unexplained #VALUE errors
That’s all great but check out the sheet that Excel Agent made with #VALUE errors all over it. Somehow the monthly payment calculation went off the rails.
It’s hard to understand how the AI Excel Agent can decide a task is completed without noticing the errors it’s made. At the very least, customers should expect some type of warning.
It’s gets stranger when comparing the Excel Agent side-pane with the sheet itself. They give different summary values in the sheet and the AI summary.
The monthly payment summary has #VALUE errors in the sheet but the Agent pane has numbers for Total Interest and Paid.
Use Agent for big jobs
Excel Agent takes some time to work, which is fine for larger “big picture” tasks like making a whole sheet.
For smaller tasks like help with a function or formula, use other tools including the Copilot pane or the AI helpers being rolled out to the formula boxes. These tools give answers in seconds not minutes.
Write the prompt carefully
Take some care writing the Excel Agent prompt. Be specific about what you want, the inputs and results to show.
Because Excel Agent takes 10+ minutes for each task, rewriting the prompt to retry the task can use up a lot of time.
How to start Excel Agent
Go to Excel on the web and look under Home | Excel Laba to see if “Agent mode (Frontier)” is offered. A Microsoft 365 licence with Copilot is necessary.
For the moment, Agent mode is only available in English and on the web. More languages and Microsoft 365 desktop apps will be added later.
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