A senior analyst, baked into Excel

Install one plugin and Excel goes from a tool you fight with to a senior analyst who builds models, reads pasted images, and rewrites entire workbooks on command.

What you'll have when you're done

A version of Excel that builds models for you, edits the ones you already have, and reads images you paste into the sidebar. You install one plugin, the Claude for Excel add-in, from Excel's built-in add-in store. You sign into your paid Claude account. Excel grows a chat sidebar wired into the active workbook.

Ask for a three-year SaaS model with growth tapering year over year. You get a three-year SaaS model, in actual cells, with actual formulas. Tell it to add a sensitivity row, rename your sheets, and reformat the headers to match a screenshot you pasted in. It does all three.

Setup takes under twenty minutes the first time and zero minutes after that. The plugin sits in your ribbon. Every workbook you open from now on can talk to Claude.

The promise: top 1% Excel competence, even if you have spent the last decade in the bottom 20%, copy-pasting SUMIFs from old workbooks and praying.

Why this matters

Excel is the CEO's working surface and the CEO's worst tool. You need a financial model, a hiring plan, a board variance table, a cohort cut. Every model gets built badly, slowly, or by someone you have to schedule a call with.

The plugin closes the gap. Claude inside Excel does not just answer questions about a sheet; it writes the formulas, builds the structure, and applies sweeping changes you describe in plain English. "Add a low / mid / high pricing scenario to every revenue row." Done. "Reformat this model to match the layout in this screenshot." Done. "Find the three cells in this workbook that don't reconcile to the summary tab and fix them." Done.

Excel skill stops being a moat for the FP&A team. The CEO who installs this on Tuesday is operating at top-1% Excel competence by Friday.

The downstream change is bigger than time saved. When the cost of running a model drops by an order of magnitude, you build more of them. You stress-test pricing twice as often. You sanity-check forecasts you would have accepted unchallenged. The decision quality of the company goes up because the bottleneck (you, in Excel, on a Saturday) moves.

What you need first

• Excel desktop. The plugin runs in the desktop version of Excel, Mac or Windows. Excel for the web has different add-in support; if you only use Excel in the browser today, install the desktop app first. [VERIFY: confirm web support status before publish.]
• A paid Claude subscription. Any paid Claude plan unlocks the plugin (Pro, Max, Team, Enterprise). The free Claude tier does not authorize the sign-in. [VERIFY: confirm the exact tier list before publish.]
• Fifteen minutes. Most of that is the install plus the first sign-in. The fun starts after.
• A real workbook to test on. Do not install the plugin and then sit there. Pick one model you have been meaning to build, or one ugly workbook you inherited, and have it open by the time you finish the install.

You do not need: Microsoft 365 admin access on most accounts, an API key, a developer plan, or any other paid tool.

Step-by-step

You install one plugin, sign in once, then run your first prompt. Five short steps, under twenty minutes.

Step 1Install the Claude for Excel add-in

1. Open Excel desktop and any workbook (a blank one is fine).
2. Click Insert in the top ribbon, then click Get Add-ins. A search dialog opens.
3. Search "Claude." [VERIFY: confirm the exact listing name. May appear as "Claude" or "Claude for Excel" or "Anthropic Claude."]
4. Click Add on the Anthropic-published listing. Excel installs it in a few seconds.
5. The plugin appears in your top ribbon and opens a sidebar pane on the right edge of the workbook.

If you do not see the plugin in the ribbon after install, restart Excel completely. Some add-in installs require a restart to register.

Step 2Sign into your Claude account

1. In the plugin sidebar, click Sign In. A browser window opens to claude.ai.
2. Sign in with the email tied to your paid Claude subscription. If you are signed into the wrong account in your browser, switch first; the plugin uses whichever Claude account your browser is logged into.
3. Approve the connection. Claude shows a permission screen authorizing the plugin to read and write the active Excel workbook.
4. Return to Excel. The sidebar should now show a chat input where the Sign In button used to be.

The most common failure here is signing in with a free Claude account. Sign out at claude.ai in your browser, sign back in with the paid account, then click Sign In in the plugin again.

Step 3Run your first prompt: build a model from scratch

The plugin works like Claude in a browser, with one new power: it can read and write the active workbook directly.

1. Open a blank workbook. (If you would rather edit an existing model, skip to Step 4.)
2. In the sidebar chat, paste this prompt:

Build me a simple three-year SaaS revenue model.
Assumptions: starting MRR $50,000, monthly growth 8% in year one,
6% in year two, 4% in year three. Show MRR, ARR, and YoY growth
in a clean monthly layout. Add a summary block at the top with
year-end MRR, year-end ARR, and the three-year growth multiple.

[VERIFY: confirm this is close to the prompt style Andrew actually uses. Adjust if his real prompts are tighter or looser.]

3. Hit enter. The plugin populates cells in real time. You will see headers, formulas, and a summary block appear in your workbook.
4. Sanity-check one formula. Click any growth cell and confirm it references the right prior period and the right growth rate. Then click a YoY cell and confirm it points to the right year-end rows.

If the model populated and the formulas reference the right cells, the plugin is working end-to-end.

Step 4Try the sweeping-edit move

The biggest unlock is not the build-from-scratch flow. It is editing models you already have.

1. Open one of your real ugly workbooks. A model someone else built. A board sheet you inherited. A pricing tracker that has grown to seventeen tabs.
2. In the sidebar, describe the changes in plain English. For example:

Change every revenue assumption on the Inputs tab to reflect a
6% price increase. Rename Sheet1 to Summary. Add a sensitivity
row at the bottom showing what happens at plus or minus 2%
growth. Keep the existing formatting on the Summary tab.

3. Hit enter. The plugin walks through the changes it is about to make before applying them. Read the plan, approve, and watch the workbook update.
4. Undo with Cmd+Z (Mac) or Ctrl+Z (Windows) if you do not like the result. Plugin edits are normal Excel operations; undo works exactly as you would expect.

The first time this lands on a workbook you inherited, you will feel the gap close. Things you would have asked someone else to do over four hours, you now do in four minutes.

Step 5Try the image-paste move

The plugin reads images. This is the cheat code.

1. Find a model or table you want to recreate. A competitor's pricing page. A screenshot from a board deck. A handwritten napkin sketch you photographed.
2. Take a screenshot. Cmd+Shift+4 on Mac, Win+Shift+S on Windows.
3. Paste the screenshot into the plugin sidebar. [VERIFY: confirm the paste mechanic. On some plugins this is drag-and-drop into the sidebar, not Cmd+V.]
4. Add a one-line prompt: "Rebuild this as a working Excel model with formulas, not pasted values."
5. The plugin reads the image, infers the structure, and builds the underlying sheet.

This is the move that puts you over the line. You stop modeling from assumption-on-a-blank-page and start modeling from the actual artifacts in your week: the screenshot a board member sent, the table in a vendor's PDF, the photo of a whiteboard from your offsite.

How you'll know it's working

After your first hour with the plugin installed, you should have:

• A model built from a prompt, sitting in real Excel cells with real formulas.
• One sweeping edit applied to a workbook you already had.
• One image successfully turned into a working sheet.

If all three worked, the install is correct and your account is authorized. The skill from here is in the prompting, not in the install.

When it breaks

• The plugin does not appear in the ribbon after install. Restart Excel completely. If still missing, go to Insert → My Add-ins and confirm "Claude" is listed. Re-enable it from there.
• Sign-in errors or a "no plan detected" message. You are signed into a free Claude account. Sign out at claude.ai in your browser, sign in with the email tied to your paid plan, then click Sign In in the plugin again.
• The plugin builds cells with static numbers instead of formulas. You asked for outputs without specifying formulas. Re-prompt with "build this as a working model with formulas, not pasted values."
• The sidebar shows a "context too large" error. Your workbook is enormous. Narrow the prompt to a single tab ("only edit the Inputs tab"), or duplicate the relevant tab into a fresh workbook for the run.
• Image paste is not being read. [VERIFY: confirm the exact image-paste mechanic. If Cmd+V does not work, drag-and-drop into the sidebar usually does.] Try the other method.
• Edits land in the wrong cells. The plugin guessed structure from your tab names and headers. Add a one-line orientation before your edit prompt: "The Revenue tab uses columns A through M, monthly across rows 5 through 28." Accuracy goes up immediately.

Where this fits in your harness

The Claude for Excel plugin is the cheapest top-1% upgrade in the harness. It does not require a terminal, command-line tools, or any custom code. It runs inside the program you already use for the highest-stakes numerical work of your week: board prep, hiring plans, pricing, forecasting.

It pairs naturally with persistent memory (Persistent memory across Claude Code sessions). When Claude already knows your past quarters' models, your assumptions, and your historical actuals, every Excel prompt gets ten times more useful. The plugin alone is excellent; the plugin with the memory layer is a different category.

Your move this week: install the plugin tonight. Friday at the end of the day, take your ugliest workbook, block thirty minutes, and rebuild it with one prompt. Send the rebuilt version to one person on your finance team. Watch what they say.