Excel: Understand Any Spreadsheet Without Reading Every Cell

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Official Anthropic skill on GitHub

Excel Spreadsheets

Summary

Someone sends you a spreadsheet. It has 40 tabs, formulas you didn't write, and your boss wants answers by 3pm.

Instead, just ask. Point Claude at any Excel file, ask what you need to know, and get answers without clicking through every tab.

Stop pretending you understand the spreadsheet your boss sent. Start actually knowing what's in it.

Ask instead of clicking

Point Claude at any workbook. Ask what's in it. Get answers without opening 40 tabs.

Write formulas in English

Describe what you need. Claude writes the formula. Copy, paste, move on.

Find the broken number

Something looks wrong but you don't know where to start. Claude traces it back and shows you exactly what's off.

Pros

  • Understand complex workbooks without clicking through every tab
  • Write Excel formulas by describing what you want in plain English
  • Find formula errors and trace calculation chains in seconds
  • Combine data from multiple tabs into clean, usable summaries
  • Your financial data stays on your machine
  • Official Anthropic skill with enterprise-grade spreadsheet understanding

Cons

  • Works with .xlsx—convert older .xls files first for best results
  • Very large workbooks (100MB+) may need to be processed in sections
  • Claude can read macro-heavy spreadsheets but can't execute VBA—it can explain what the macros do

How to Use Excel Spreadsheets Skill

Skill command:
1

Install the Skill

Install via the plugin marketplace, or download the skill file directly. Skills auto-activate when relevant—no manual invocation needed.

Option 1: Plugin Marketplace
/plugin marketplace add anthropics/skills
/plugin install document-skills@anthropic-agent-skills
Option 2: Direct Download
curl -o .claude/skills/xlsx.md https://raw.githubusercontent.com/anthropics/skills/main/skills/xlsx/SKILL.md
2

Ask What You Need

Be specific. "What formula drives cell B47?" beats "analyze this spreadsheet." The more precise your question, the more useful the answer.

Example Prompt
Walk me through this workbook. Which tabs have real data? What formulas drive the summary? Any errors or circular references?
3

Point to Your File

Drag the spreadsheet into your terminal or paste the path. Your financial data stays on your machine.

Example Prompt
Analyze ~/Finance/Q4-Actuals.xlsx. Compare "Actuals" vs "Budget". Show me the top 5 line items where we missed forecast by more than 10%.
4

Keep Drilling

Claude remembers the spreadsheet. Ask follow-ups. Dive into specific tabs. No need to re-upload.

Example Prompt
That Marketing overspend looks wrong. What formula calculates that cell? What inputs is it pulling?
5

Get Output You Can Use

Summary tables. New formulas to paste back in. Cleaned data for your BI tool. Whatever format you need.

Example Prompt
Create a summary table: each department's budget vs actual vs variance. Format it for a slide deck.

Example Prompts

Real-world scenarios showing how to use Excel Spreadsheets effectively

Scenario: Figure out a spreadsheet you didn't build

Your Prompt

/xlsx Before I touch anything, map this workbook. Which tabs have data vs. reference tables? What's the calculation flow? Flag anything fragile—hardcoded numbers, circular refs, formulas that might break.

Expected Outcome

Claude maps the structure, explains the data flow between tabs, flags potential landmines. You understand the spreadsheet before you break it.

Scenario: Track down a wrong number

Your Prompt

/xlsx The "Total Revenue" cell shows $4.2M. My back-of-envelope says $3.8M. Trace that formula back to source and tell me where the $400K gap is coming from.

Expected Outcome

Claude traces the formula chain, identifies all source cells, and pinpoints where the numbers diverge—whether it's a formula error, double-counting, or bad input data.

Scenario: Write a formula you can't figure out

Your Prompt

/xlsx Write me a commission formula: 5% on the first $100K in sales, 8% from $100K-$250K, 10% above $250K. Sales in column D, starting row 2. Make it copyable down the column.

Expected Outcome

Claude writes the exact formula with proper cell references, explains how it works, tells you how to apply it. Copy, paste, done.

Scenario: Combine data from multiple tabs

Your Prompt

/xlsx This workbook has 12 tabs—one per month. Same structure: Product, Region, Units, Revenue. Combine all 12 into one table with a Month column added. I need it for pivot table analysis.

Expected Outcome

Claude extracts and consolidates all tabs into a single clean dataset. Paste it into a new sheet or your BI tool.

Scenario: Board meeting in two hours

Your Prompt

/xlsx Board meeting at 3pm. From this Q4 workbook, give me: (1) Top 5 revenue drivers vs last quarter, (2) Three cost categories that grew fastest, (3) Cash trend month-over-month. Bullet points for speaker notes.

Expected Outcome

Claude pulls the metrics, formats them as talking points. You walk into the boardroom prepared, not panicked.

Frequently Asked Questions

Yes. Describe what you need: "sum revenue by region, but only for Q4." Claude writes the formula with proper syntax—VLOOKUP, INDEX/MATCH, nested IFs, array formulas, all of it. Paste directly into Excel.
Claude Code works directly with your file. It navigates tabs, traces formulas across sheets, and remembers context for follow-ups. ChatGPT requires copy-pasting data and loses the workbook structure. For anything beyond simple formulas, Claude Code is significantly more capable.
Claude processes files locally—your spreadsheet doesn't get uploaded anywhere. Contents are sent to Claude's API for analysis but aren't stored. Check your organization's AI policies for confidential data.
This is actually one of the best use cases. Claude can identify formula errors, trace circular refs, and explain where calculations break. "Why is this cell showing #REF?" becomes a 30-second fix instead of an hour of detective work.
Claude reads data from pivot tables and describes chart configs, but works primarily with underlying data. Need a new pivot table? Claude tells you exactly how to set it up—it just can't manipulate the Excel UI directly.
Most business spreadsheets work without issue. For very large files (thousands of rows across many tabs), ask focused questions about specific tabs rather than "analyze everything." Claude will suggest how to break it up if needed.

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