Claude in Excel: Add-in Setup, Plans, Mac, MCP and Fixes

Claude works in Excel through Anthropic’s add-in, Claude for Excel. It opens as a sidebar beside your workbook, where you can ask it to explain a formula, trace a #REF! error to its cause, or build a three-statement model from a trial balance. It needs a paid Claude plan and Excel on the web, on Windows with Microsoft 365, or on a Mac.

This guide starts there: getting the add-in, what it costs, what it can do, and fixes when it won’t show up. Every fact about Anthropic’s and Microsoft’s products comes from their own pages, read November 4, 2026.

Two more routes follow. An Excel MCP server lets Claude Code, Claude Desktop or Codex edit .xlsx files on your computer. And a spreadsheet that lives online, like a Context Board Sheet, lets Claude, Codex or ChatGPT add rows from wherever they run, with no Excel open. Context Board is ours, so weigh the bias.

How to get Claude in Excel

Anthropic calls the add-in Claude for Excel. AppSource lists it as Claude for Microsoft 365, since one listing covers Excel, PowerPoint, Word and Outlook, and many guides say Claude in Excel. All three mean the same add-in. The install, from Anthropic’s Excel docs:

1. Open the listing. Go to the Claude for Microsoft 365 listing on Microsoft AppSource.
2. Install it. Select Get it now.
3. Activate it and sign in. Open Excel, go to Home, then Add-ins on Windows, or Tools, then Add-ins on a Mac, pick Claude and sign in with your Claude account.

Which plans: Anthropic’s pricing page lists Claude for Microsoft 365 on Pro, Max, Ultra, Team and Enterprise, and not on Free. Pro is $20 a month, or $17 a month billed yearly, and Max starts at $100. The add-in has no separate price, and Anthropic says it is subject to the same usage limits as the rest of your Claude account.

Which Excel: check this before anything else.

At work: an admin may have to deploy it. In the Microsoft 365 admin center, Anthropic’s steps turn on “Let users access the Office Store” under Org Settings, then assign Claude for Microsoft 365 to people or groups from Integrated apps. Where the Office Store stays off, Anthropic offers a manifest file to upload instead.

Through Copilot: if your company pays for Microsoft 365 Copilot, its model picker in Excel supports the latest Anthropic models, once an admin allows them. That is Microsoft’s Copilot running a Claude model, a different product from Anthropic’s add-in.

What Claude for Excel can do, and what it can’t

Anthropic’s docs list what the add-in does inside an open workbook.

• Answers that cite cells: each answer links the cells it used, so you can click through and check.
• Edits that keep formulas: it updates values while keeping formula links intact, so the cells downstream recalculate.
• Models from a sentence: it fills a template or builds a new model from a description, and finds the root cause of a calculation error.
• Excel’s own tools: it sorts, filters, edits pivot tables, applies conditional formatting and makes dropdowns, across workbooks with many tabs.
• A warning first: it warns before writing over existing data, and asks you to confirm a risky operation.
• Connectors and Skills: the + under the chat box opens Connectors, such as S&P Global and LSEG for financial data, and Skills you have turned on in Claude’s settings work here too.
• Work across apps: it shares context with Claude for PowerPoint, Word and Outlook, so it can put numbers from an Excel model into a slide. The setting, “Let Claude work across files”, starts on for Pro and Max. Our guide to making slides with Claude covers the PowerPoint side.

What it can’t do: Anthropic lists data tables, and macros and VBA, as unsupported. Claude only works on files open in Excel, PowerPoint or Word, and can’t open or switch files itself. Anthropic doesn’t recommend it for final client deliverables without human review, or for audit-critical calculations without checking.

What to watch: use it only with spreadsheets you trust. Anthropic warns that a file from outside can hide instructions that push the add-in to pull data out, change records or delete things. Work on a copy before wide edits.

Where your chats go: chat history stays in your browser, and Anthropic deletes inputs and outputs from its backend within 30 days, per its data storage page. A long modeling session draws on the same pool as your chats, and our guide to Claude’s usage limits shows how fast it goes.

Claude add-in not showing in Excel? What to try

Anthropic’s docs cover each usual cause. Work down the list.

1. Check the plan. Sign in with the Claude account that has Pro, Max, Ultra, Team or Enterprise. A Free account can’t use it.
2. Check your Excel against the table above. Excel 2016 or 2019 bought outright, iPad and Android won’t run it, and an old Microsoft 365 build needs updating. Excel on the web is the fallback.
3. Activate it. Installing isn’t enough. Open Home, then Add-ins on Windows, or Tools, then Add-ins on a Mac, and pick Claude.
4. On a work account, ask IT. If your company has turned off “Let users access the Office Store”, add-ins can stay hidden and you can’t add one yourself. Anthropic also notes a known Microsoft issue: deployment fails for admin roles switched on through PIM, so deploy from an account whose role is permanently active.
5. Sign-in says your browser couldn’t be verified. Your network may block hcaptcha.com, which the sign-in uses.
6. Your chat history vanished on Windows. Microsoft 365 Version 2608 and 2609 can open the add-in on a new, empty storage folder. Don’t clear the Office add-in cache, which deletes the old data. If Office switched you to another account, sign back in to the original one.
7. Claude can’t see your other open file. Make sure the add-in is active in each app, and turn on “Let Claude work across files” in its settings.

Use Claude with Excel files through an MCP server

The add-in puts Claude inside Excel. An MCP server turns that around: your agent stays in Claude Code, Claude Desktop or Codex, and the server gives it tools to open and change spreadsheet files. Our guide to MCP explains the protocol.

Two open-source Excel MCP servers cover most needs, and both are MIT licensed.

Set up the first one. Its README says you need uv. Then it is one line in Claude Code or Codex, naming the folder the server may touch:

# Claude Code
claude mcp add excel --scope user -- uvx excel-mcp-server stdio --allow-dir /path/to/workbooks

# Codex
codex mcp add excel -- uvx excel-mcp-server stdio --allow-dir /path/to/workbooks

Start a new session afterwards, since both apps load MCP servers when a session starts. In Claude Desktop, the README’s quickest route is to download excel-mcp-server.mcpb from the latest release and open it. Claude asks which folder the server may use.

What it can do: its README lists tools for sheets, ranges, formulas, formatting, tables, charts, pivot tables and data validation, with formulas worked out by its own engine of about 260 functions. It handles .xlsx and .xlsm files, but not the old .xls format.

What to know: it changes files on disk, and what the agent reads goes to its model, so use trusted files here too.

Claude Excel skills on GitHub: Anthropic’s skills repo has the xlsx skill behind Claude’s spreadsheet files in a chat. It is source-available, under a proprietary license.

Work on a spreadsheet without Excel open

The add-in needs Excel running, and an MCP server needs an agent on your computer. Three routes skip both.

• Excel on the web: the add-in runs there, so a browser is enough. Anthropic says to treat chat history in Office on the web as temporary.
• A file in a Claude chat: with file creation, Claude makes Excel files on every plan, Free included. Upload a CSV, ask for a cleaned-up workbook with a summary tab, and download the .xlsx. Files are capped at 30 MB, and making them uses more of your limit than a normal chat.
• Excel files in OneDrive or SharePoint: Claude’s Microsoft 365 connector, on every plan, reads Excel files in OneDrive, and in SharePoint on a work account. With write tools on, it can create and update files there, and in chat Claude asks before it changes anything.

Each of these is one Claude on one file, and your other agents never see it. If Claude, Codex and ChatGPT all touch the same numbers, they need one sheet they can all reach. That shared place is what people mean by an agentic workspace.

A spreadsheet your agents fill in: Context Board Sheets

Context Board is a web app at board.contextbolt.com, a workspace you share with your AI agents. A Sheet board is one of its kinds of board: tabs of cells and formulas, like the sheets you know, that your agents read and write over MCP. Claude, Codex, Cursor, Grok and ChatGPT (on plans that allow a custom connector) all work in the same sheet.

• Formulas you know: more than a hundred of the everyday Google Sheets functions, from SUM and IF to SUMIFS, XLOOKUP and FILTER, with references across tabs. Change a number and every cell that reads it works itself out again.
• Your Excel files, every tab: import an .xlsx, .xls, .ods or CSV file of up to 40 MB. Each tab comes in with its formulas, number formats and column widths.
• Agents that add rows: your agent reads a tab as a table and writes cells, rows, formulas, formats and sorts. It can add a tab, make a table whose new rows take its column formulas, and chart a range.
• A name on every change: cells an agent writes glow once in its color, with a flag carrying its name. Board activity lists each change, and when an agent writes over filled cells, that line has Undo.
• Charts that follow the sheet: chart a range beside the cells, or put it on a Slides board, and the chart changes when the sheet does.
• Excel back out: download a tab as CSV, or the whole sheet as .xlsx with its values, formulas, number formats and widths.

A tab holds up to 10,000 rows and 104 columns, and a sheet up to 40 tabs. A first sheet goes like this.

1. Make a Sheet board. Choose New board, then Sheet.
2. Bring your workbook. Choose Import a CSV or Excel file, on the left, and add its tabs as new tabs.
3. Connect your agent once. For Claude Code or Codex, link your computer with the one line from Connect. For Claude, ChatGPT or Cursor, add the board’s address in the app and click Allow.
4. Ask for the work. For example: “On my Running costs sheet, add the analytics tool at $19 a month to the Costs tab.” The row lands with its yearly total, glows in the agent’s color, and the totals move.
5. Check it and pass it on. Read the change in Board activity. Share a read-only link, or download the .xlsx when someone needs a file.

Your agent reaches the sheet from wherever it runs, Claude on the web or Codex in a terminal, with no Excel open. Context Board is free for 3 days, then $12 a month for every kind of board, sheets, docs, slides and dashboards included. Your agents work on the plans you already pay for, so there are no AI credits to buy.

When the add-in is the better tool: if you live in Excel all day, keep Anthropic’s add-in. It works inside the workbook you have open, with your pivot tables, your firm’s templates and answers that cite cells. A Sheet board isn’t Excel. It has no pivot tables or macros, and its .xlsx download leaves charts and color rules on the board. Pick the board when a sheet is something several agents keep current, next to the docs, decks and dashboards they also work on.

Which way to use Claude with Excel

Each route puts your spreadsheet in a different place, and that decides which agents can reach it.

If ChatGPT is your main AI, OpenAI makes its own add-in, ChatGPT for Excel, and its help center has the details.

Start with the question you have today. If your numbers live in Excel and so do you, install the add-in and ask it about a model you already know, so you can check its answers. If Claude, Codex and ChatGPT should all keep one sheet up to date, put it on a Context Board Sheet, import your workbook with every tab, and ask your agent for the first row.