What if your Excel could not just suggest — but actually think, take decisions, and build models on your behalf? That is Agentic AI. And Claude is right here, inside your Excel. In this post I walk you through exactly what happened when I gave Beast one prompt — what it built, where it stumbled, how it corrected itself, and what that tells us about the future of AI-assisted analysis.

What Is Claude for Excel?

Claude for Excel is an official add-in from Anthropic that brings Claude — one of the most capable AI models in the world — directly into the Microsoft Excel sidebar. It is not a formula suggestion tool. It is not an autocomplete. It is a full agentic AI that can read your entire workbook, understand the logic, and make changes — all while explaining every step it takes.

Think of it as having a senior analyst sitting next to you inside Excel, one who never gets tired, never misses a formula dependency, and can build a multi-sheet analysis from a single plain-English instruction.

Which Claude Plan Do You Need?

The add-in is free to install from the Microsoft Marketplace — but you need a paid Claude subscription to use it. Here is the current plan availability as of March 2026:

Which AI Model Powers It?

Claude for Excel runs on Anthropic’s Claude model family. You can choose your model directly from the sidebar. The current Claude 4.6 family gives you three levels of power:

For everyday tasks — quick summaries, formula fixes, data cleaning — Sonnet 4.6 is faster and equally impressive. But when you want Beast to build something complex from scratch, give it Opus and step back.

System Requirements

Before you install, make sure your setup meets these requirements:

Note: Claude can read and analyse .xlsm files (Excel with macros), but it cannot execute or modify VBA macros. It can work with the structure and formulas — macro logic remains outside its scope.

How to Install Claude for Excel

• Open Excel and go to Add-ins On Windows: Home → Add-ins. On Mac: Tools → Add-ins. On Web: Insert → Add-ins.
• Search Microsoft AppSource Type “Claude by Anthropic for Excel” in the search bar and find the official add-in.
• Click Add / Get It Now The add-in is free to install. No payment needed at this step.
• Sign in with your Claude account Use your Anthropic / Claude.ai credentials. This is where your subscription is verified.
• The Claude sidebar opens — you are live Claude is now inside your Excel. Open any workbook and start talking to your data.

For IT administrators deploying to multiple users across an organisation, Anthropic provides a manifest XML file for bulk deployment through the Microsoft 365 Admin Center under Settings → Integrated Apps.

What Actually Happened in the Demo

I had one sheet. 100 rows of basic sales data — City, Region, State, Sales Amount, Units Sold, Product Category, Sales Rep, Discount. No pivot tables. No formatting. Just raw data.

I gave Claude one prompt. No instructions about sheets to create, no mention of charts, no formatting specs. Just a direction: prepare a complete board-ready analysis for senior management.

Here is what Claude built — entirely on its own:

Where It Stumbled — And How It Fixed Itself

This is the most honest and important part of the demo. Claude is powerful — but it is not perfect, and knowing where it needs guidance is what separates a good user from a great one.

In the Regional Analysis sheet, I noticed that Region and State values were hard-coded — written directly as text rather than pulled from the source data using formulas. This means if you refresh the source sheet with new states or regions, those cells would not update automatically. It would break the whole workbook.

I gave Claude a second prompt explaining exactly this. Its response was immediate and honest — it acknowledged the mistake, accepted that a board-ready workbook should be fully dynamic, and corrected it. It replaced the hard-coded values with dynamic array formulas using SORT and UNIQUE — exactly what a senior Excel developer would use on the latest Excel version.

The Iterative Loop — Adding Discount Analysis

After the main workbook was complete, I noticed something missing. There was no analysis on discounts — and discount impact is exactly the kind of question that comes up in a board review meeting.

I gave Claude a third, simple prompt: “I don’t see any analysis on discount. Can we have one sheet for discount-related analysis for the management audience?”

Claude created an entirely new sheet — Discount Analysis — with discount buckets (0–10%, 10–15%, 15–20%, 20%+), revenue by discount band, and volume analysis. And importantly, this time it did not repeat the earlier mistake. The new sheet used dynamic formulas throughout — no hard-coded values. It had learned from the earlier correction and applied that standard to the new work.

That is what agentic AI looks like in practice: not a one-shot output, but a conversation-driven build loop where you drive the outcome and the model executes with increasing accuracy.

Claude for Excel vs. Microsoft Copilot in Excel

Things to Keep in Mind

Claude for Excel is still in beta — which means it is powerful, but not perfect. A few practical notes before you go live with it:

Final Word

My focus in this video was not what analysis Claude would produce. The focus was the possibilities — what it can do, and how you can drive automation in your daily routine.

Claude built six sheets from one prompt. It created charts, calculated ranks, wrote dynamic formulas, cross-verified its own numbers — and when a chart failed, it adapted and built a different one. When I pointed out a structural flaw, it accepted the feedback, corrected the mistake, and applied the improved standard to all subsequent work.

That is not a feature. That is a thinking collaborator inside your spreadsheet.

For CA firms, internal audit teams, financial analysts, and anyone whose job involves turning raw numbers into decisions — Claude for Excel compresses hours of work into minutes. But the professional judgment, the quality bar, the domain knowledge — that still comes from you. Claude executes. You lead.

Start using it. And when you do — stay in the driver’s seat.