Formula Helper vs. Financial Modeler

If you’re using Copilot like this: type a question, get a formula, apply it, move to the next cell, repeat.

That was fine in 2024. This is not fine in 2026.

Microsoft have just rebuilt the Copilot experience in Excel and renamed Agent Mode to “Edit with Copilot” because ‘agentic’ editing is now what Microsoft are moving toward as standard.

If you’re still prompting Copilot one cell at a time, you’re running 2024 software in your head on top of a 2026 tool.

And this is costing you hours every week.

So, today I will teach you how to use ‘Edit with Copilot’ to build auditable models using only Excel, in 5 minutes or less.

Tell Copilot What to Build, Not What to Do

Stop asking for help with this cell. Start asking for help building this model.

Edit with Copilot plans a multi-step approach, executes across multiple tabs, creates formulas that reference each other, builds charts, and self-corrects when something doesn’t work.

I show this live during my webinars. And, in just 5 minutes, Excel creates a perfect three-statement financial model.

All I needed was this prompt:

And the model it builds is linked. I can test it by changing assumptions and the entire model updates. If I edit the formulas, I can check if everything stays connected.

Plus, you can now pick which AI model you want to use.

Click the model picker in the Copilot pane and choose between Auto, GPT-5.2, Claude Opus 4.5, or Claude Opus 4.6.

For financial modeling where you need reasoning chains, assumption logic, and scenario structures, Claude is the better choice.

Previously Microsoft decided for you. Now you pick the model that’s best for your finance work.

How to Start Using ‘Edit with Copilot’

Step 1: Open Excel

Click Copilot in the ribbon. Click the “+” and then select “Edit with Copilot.”

That’s where Agent Mode lives now.

Step 2: Choose model

Click the model picker at the top of the Copilot pane. Switch from Auto to your preferred model.

Step 3: Test it out

Write one prompt that describes the outcome, not the steps.

Here’s mine:

Step 4: Watch it build

Copilot shows its reasoning. You can click the “Reasoned in..” dropdown.

It created tabs, linked formulas, and generated charts.

When it finds errors, it fixes them.

Step 5: Review output

The most important step of all, you need to review it like you’d review a junior’s work. Change an assumption and check if the model updates.

But you don’t audit this by recalculating every formula yourself. You ask Copilot to build the audit for you.

Two more things to do.

1. Ask Copilot to include an assumption sheet. All your salary increases, tax rates, growth rates in one place. This makes the model auditable and easy to flex
2. Ask Copilot to add reconciliation checks:

Make Copilot document its own logic and prove the numbers work. Then you review the checks instead of the the entire model.

Treat it like delegating to a junior team member. You still sign off before anything goes anywhere.

Because, AI still makes mistakes like a human. But this way, your audit trail is built in, and much easier to review than trying to unpick everything afterwards.

The One Thing to Remember

This is a direct quote from me after building a complete financial model inside Excel with a single prompt.

I didn’t need to open ChatGPT, copy and paste. All I had is Copilot with Claude doing the work inside the spreadsheet.

Agent Mode didn’t disappear. It just evolved. And now, with Claude inside Excel, you have the best reasoning model available working directly in your financial models.

Stop asking Copilot for formulas. Start telling it to build your models.

The tool is ready. The only question is whether you’ll update how you use it.​