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Hey Reader,

Claude is inside Excel now.

And no, I do not mean the thing where you screenshot your spreadsheet and paste it into a chat window. Claude can actually see your workbook, read your formulas, and make changes directly in your file.

Most people I talk to either have not heard of it yet or installed it and had no idea what to do next.

So I walked through the whole thing. Setup, security, what it can actually handle, and where it still falls short.

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You can install Claude for Excel from Claude's website, or just open Excel, click Add-ins, and search for Claude. Pretty straightforward.

Once it is installed, you connect it to your Claude account. And right away, the first thing worth knowing hits you.

Your usage is tied to your Claude plan, and file work burns through credits way faster than a normal chat conversation. If you are doing serious Excel work, you probably need the max plan. Just something to keep in mind before you get too deep.

Now on the security side, Anthropic says your data is encrypted in transit and at rest. But here is the catch. On consumer plans, your chats may be used to improve Claude unless you go into settings, click privacy, and turn that off yourself.

Once all of that is squared away, there is one more thing that makes a real difference.

Claude's output is only as good as the file and the prompt you give it. A clean workbook with clear tabs and solid formula logic will always produce better results than a messy one.

And here is a trick I picked up along the way. Before I use Claude for Excel, I ask Claude to help me write the best prompt for the task first. Then I take that exact prompt and paste it in. Sounds like an extra step, but it saves a ton of time later.

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More than most people expect.

I started by asking it to take a monthly profit and loss and create an annual summary. Simple enough, right?

But what it did was actually smart. Instead of summing random ranges, it wrote a SUMIF formula that matched the year in my helper row and pulled the right amounts. Then it noticed I had 2026 data in my monthly section with no annual counterpart, so it just went ahead and added a 2026 column on its own.

I did not ask for that. That is not a formula generator. That is judgment.

Now here is where it really started to impress me.

I asked it to build a three-statement model from a real income statement and balance sheet. Halfway through, it made an error, referencing the wrong column. But before it submitted anything, it reviewed its own work, caught the mistake, and fixed it.

That is when I realized this was not just an Excel tool with a chat window. This was combining real LLM thinking with actual finance knowledge.

And it goes further than just knowing formulas. When I told it I run a SaaS business and asked for a revenue forecast, it built an MRR waterfall with benchmark sources, assumptions about churn and net dollar retention, and color coding that followed best practices. I never spelled any of that out. It just knew.

It can even build CFO-grade dashboards with period comparisons, conditional formatting, and written commentary. The kind of output you would actually present to a board.

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Now before you get too excited, there are some real limits.

When Claude built my three-statement model, it hard coded some subtotal values instead of writing formulas. That means if you change an assumption upstream, those subtotals just sit there. In a real financial model, everything needs to tie together dynamically. Hard coded values break that.

That is actually why I built Model Wiz. So you start with a three-statement model where every formula is already connected the right way. You can check it out here.

I also tried asking it to do something more complex, rolling forward my file with new accounts and adjusting the forecast. It timed out and gave up.

Oh, and my Excel file crashed twice while Claude for Excel was working on it. I still do not know why. So back up your files before you start. I learned that one the hard way.

So here is how I would think about it. Use Claude for Excel to speed up work you already understand. Filling in formulas, adjusting assumptions, building out sections in a model you have already structured. Do not hand it a blank file and hope for the best.

When I first installed Claude for Excel, I spent about an hour just seeing what it could do. Watching it build formulas I would have written myself but in a fraction of the time.

At some point it hit me that this is not about whether Claude can replace an analyst. It is about whether you are willing to learn how to work alongside one that never sleeps and occasionally hard codes a subtotal just to keep you on your toes.

What part of your Excel workflow would you hand to Claude for Excel first?

Hit reply and let me know.

Josh

Your CFO Guy

Quick note: While I love sharing my finance & accounting knowledge, remember I'm Your CFO Guy, not Your Personal CFO. Everything I share comes from my experience, but each business is unique. My content is educational, not professional advice - always consult with your own qualified advisors for decisions about your specific situation.