Using Copilot with Excel – what I train

I’ve only recently started including material on using Copilot with Excel in my bespoke training courses.

The reasons for my reticence are as follows;

• it’s not actually very useful to me at present. So it’s hard for me to deliver convincing training material.
• it is not consistent. So if you show an example of a prompt, you can’t rely on it giving you the same answer twice.
• The key to getting better results from Copilot seems to be prompting it with a lot of detail, which requires a good underlying knowledge of Excel in the first place.

However, I wouldn’t be much of a trainer or a consultant if I didn’t check in with it regularly to see if it has improved. Microsoft are constantly pumping updates to it and adding new products. For example “Agent Mode” is rolling out – I don’t have it yet but when I do I’ll want to test it.

And the constant refrain has been (I’m paraphrasing): Sure, it might give you crazy formulas and inaccurate results but look how fast it does it and how clever it sounds! And in the future maybe it will also work reliably!

Why am I now including material on Copilot with Excel?

It’s clear that Copilot isn’t going away anytime soon. Microsoft are embedding it in more and more places within their products. At one point the icon even followed you around your spreadsheet like a hopeful puppy.

Even if you don’t want to use it, you might find it difficult to avoid. So I want to make sure you understand its limitations and how to get the best out of it.

My tips for using Copilot with Excel

As at November 2025, here are my views on using Copilot with Excel. They may change in future; I accept that it is a rapidly changing field.

• You should not use it for anything mathematical or analytical. I.e. don’t get it to analyse or summarise your data. Aside from any issues about using your data for training, this is just a rubbish use of a computer. Using a computer to do complicated probability maths to make an educated guess as to what the answer might be is a lot less desirable than using the computer to do the simpler maths directly to give you the right answer. So ask it how to do these things with reliable Excel functions, rather than trying to skip straight to the answer.
• Obviously be as precise as you can with the prompt. If you know you need to use Power Query to solve it then specify that in the query, and give an example of your data set.
• it has a better hit rate on questions that relate to technology that has been around a while. This is because there is a lot more data out there for it to steal from. I have had better luck with prompts about M code or DAX than I have about dynamic arrays. But you can still waste a lot of time because…
• … it has optimism bias built in so it’s really bad at telling you that something isn’t possible. It will send you round on a little loop suggesting slightly different answers for ever, as far as I can tell.
• if you are going to use it, make sure you’re using it with “Enterprise protection”. You can tell this because you have a little green shield. Beware! If you search for Copilot on your computer, you’ll probably get the version built into Windows 11, which doesn’t have this protection.

My overall conclusion is this.

If you are stuck on something Excel or Power Query related, you’re still better off doing a site specific website search on a trusted expert’s site such as Excel off the Grid or Goodly.

Ironically, search results on the wider web have been polluted by lots of generic (and often incorrect) AI generated blog posts about Excel.

And ultimately, the best way for you to learn something is to try to do it yourself.

Other LLMs are available

Other Large Language Models such as ChatGPT, Claude and Gemini are available. However, I’m already wasting enough time trying to get one to work properly. The one that’s supposed to be integrated with the software I love. When there is reliable evidence of proper Excel geeks using any LLM to genuinely enhance their workflow, I’ll be all over it.