I made a big mistake by ignoring Claude for too long. It's now really good at finance use cases. (Plus, you can use it in Excel now too...)

You’re probably still building models the hard way. Cell by cell. Formula by formula. Then spending another 30 minutes making it look good for your colleagues.

It’s hard for you to come up with an Excel file that works with formulas (that also looks good) without spending hours.

And, the gap between finance pros using AI for model building and those still doing it manually is getting wider every week.

Today I want to show you how to close that gap.

​

​
Manually - Brick by Brick

Here’s how you build a financial model right now.

You open a blank Excel file. You set up your structure manually. You write formulas cell by cell, testing as you go. Then you realize you made an error somewhere in row 47 and spend 20 minutes fixing it. .

And after all that? You still need to make it look decent for your CFO or your board.

This is construction work. And, it's the lowest-value use of your time as a finance professional.

The obstacle here is not your skill (you know how to build models). The problem is you're doing mechanical work that AI can now handle faster and more accurately than any human.

​

​
The Architect Approach

Think of it like this. An architect doesn't lay the bricks. They design the building and let somebody else handle the construction.

AI lets you operate like an architect of financial models. You still need to know what a good SaaS revenue model looks like. You still need to understand growth rates, churn, and scenario logic (that's your expertise and AI cannot replace it).

But the cell referencing, the formula syntax and the formatting can now be automated..

In one of my recent videos, I showed three ways to use code to build a dynamic financial model.

First, directly in Claude as an interactive web model. Then exported as an Excel file with formulas. And finally, the best way (running directly inside Excel using the Claude plugin).

You are the architect -> Claude is the bricklayer.

Let me walk you through each one.

​

​
Three Ways to Build Your Model

It’s best to use Claude for Business / Enterprise to be super secure.

Method 1: Interactive Web Model (Great for Meetings)

Here's the prompt structure that we used for all three use cases. We always give the context first.

The prompt looks like this:

Really important is to use Opus 4.5. This is the best model for code on complex topics.

After a few seconds, Claude builds the model and you can change it directly inside. If you have a meeting, you can adjust all of the assumptions live. The graphs change in real time. You can change the churn, the price, the starting subscribers. Everything is dynamic.

And you can even share it with a colleague. When they open it, they get a page where they can play around with the model and change assumptions.

(a member of my team actually did this with our sales projections for this year)

This is perfect for live discussions with your boss or a client where you need to answer "what if" questions straight away.

​

Method 2: Excel Export with Formulas

The web model is great for meetings, but sometimes you need the file in Excel so you can edit it further or integrate it with your existing work.

For this, you:

1. Use the same prompt as above
2. Add at the end that you want to build an Excel file with formulas.

Really important: if you want to create Excel files, you need to make sure that in your settings, code execution and file creation is activated.

Claude uses Python to create the Excel file. What you’ll see is the Excel file being built on the right side of the screen (I like being able to see this).

The formatting should also be really good. So imagine the time you can save here.

When you download and open the file in Excel, the formulas should work, and everything should be linked.

Plus, each time when you touch the assumptions, the graphs should change.

You will be surprised how fast Claude can build this and how pretty the file will look.

Even me, I would not have come up with something that professional in such a short time.

​

Method 3: Build Directly in Excel (The Best Way)

The third method is to build the model directly in Excel using the Claude plugin. You can install it by going to the Claude for Excel page. At the time of this newsletter, Claude in Excel is currently in beta and available to Pro, Max, Team, and Enterprise plans.

But, once connected, you can select cells and ask questions, build financial models, and even debug and fix errors.

So:

1. Use the same prompt
2. Claude will start thinking through the model first.
3. Then it will ask if it can enter the spreadsheet and make changes.
4. When you allow this, it will start building directly in Excel.

When I ran this it automatically generated the model with colours, the headers had grey backgrounds, and it gave a summary at the bottom. It even changed the column widths (super impressive).

What’s better, you don't need to leave Excel at all. The model gets built where you already work!

Which Method Should You Use?

​
Method 3 (Claude in Excel) is best for most finance professionals. If you spend most of your day in Excel and produce Excel-based work, stay in Excel. This avoids a lot of switching between apps.

Method 1 (Interactive Web Model) is best when you want to build something interactive to share with others, or when you need a quick visual tool for a live meeting.

Method 2 (Excel Export) is best when you're already in a Claude conversation and want to turn your discussion into a workable Excel file.

For 80% of finance use cases, Method 3 will be best.

Resources:

• Claude for Excel plugin: Claude in Excel​
• My Excel Agent Mode YouTube Video: Watch here​
• My previous newsletter on ChatGPT Agent Mode: Read here​

The One Thing to Remember

AI doesn't replace your financial thinking. It eliminates the build time so you can focus on the analysis.

Building the model is not the work. Your work is thinking, advising, and creating impact for the business.

And now you finally have the time to do this.

So, act like an architect, use AI as your construction worker, and together you can build amazing things.

​

Best,

Your AI Finance Expert,

Nicolas

​

P.S. What did you think of this one? Was it useful? Hit reply and let me know (I read all replies).

P.P.S - This newsletter is based on my latest YouTube video where I walk through all three methods live, including the exact prompts and settings you need. Watch it here: How to Use Claude to Build INSANE Financial Models (2026)​

​

​.​