Claude for Excel: what it does and how to use it safely

What Claude for Excel is

Claude for Excel is an add-in that brings Claude into Excel on the web, Windows (with a Microsoft 365 subscription) and Mac. Anthropic lists it as generally available on its Pro, Max, Team and Enterprise plans, and it uses your existing Claude account and its usage limits.¹

What it can do

• Answer questions about an open workbook, with citations you can click to jump to the cells it used.
• Change assumptions while keeping formula relationships intact, so dependent cells recalculate correctly.
• Find the root cause of errors such as #REF! or #DIV/0!, and suggest fixes.
• Build a new model from a description, or fill in an existing template.
• Work across multi-tab workbooks, and handle everyday tasks like sorting, filtering, pivot tables, conditional formatting and dropdowns.¹

Good first prompts are simple and specific:

• Walk me through how the total in cell C42 is calculated.
• What assumptions drive the margin forecast on the Summary tab?
• Change the growth rate to 5% and show me what changes.
• Find the source of the #REF! error on the Summary tab.

Setting it up for your team

1. Individuals can install the Claude for Microsoft 365 add-in from Microsoft AppSource and sign in with their Claude account.
2. For the whole organisation, a Microsoft 365 admin can deploy it from the Admin Center under Integrated apps, to everyone or to chosen groups.
3. Set persistent instructions in the add-in, such as number formats and currency, so every conversation follows your conventions.¹

Limits and data handling

Anthropic says Claude for Excel is not recommended for final client deliverables without human review, audit-critical calculations without verification, or models containing highly sensitive or regulated data without proper controls. It does not support Excel data tables, macros or VBA.¹

Conversations, including the content Claude reads from your workbook, are sent to Anthropic. Inputs and outputs are deleted from Anthropic's systems within 30 days, with stated exceptions, and chat history is kept locally in your browser. On Enterprise plans, the add-in does not inherit custom retention settings and its activity does not appear in audit logs, so check how it fits your policies.¹²

Use it safely

• Only use it with trusted spreadsheets. Anthropic warns that files from outside sources can contain hidden instructions that try to manipulate the add-in.
• Work on a copy of an important workbook before asking for wide changes.
• Read every confirmation before you approve a change, and check results against your own judgement.
• Keep personal and sensitive data out. Anonymise figures where you can; most analysis works just as well without names.¹