Claude's Excel skill: messy export in, clean workbook with formulas out

Set up and upload

1. Account menu, Settings, Capabilities: turn on Code execution and file creation.
2. In a new chat, click +, then Upload or add files, and pick your CSV export.
3. Paste the request below and send it.

Say exactly what you want

This is our [SYSTEM] export for [PERIOD]. Clean it up and turn it into an Excel workbook with: a Data tab with one clean row per sale (one date format, amounts as numbers, no duplicates or subtotal lines, consistent category names), a Summary tab with total sales by month and category using formulas, and a column chart of monthly sales by category. Tell me what you changed.

Open the line above the reply and look for Loaded skill xlsx.

Read what Claude changed

• The lesson's list: title lines skipped, dates in one format, text amounts made numbers, category spellings merged, 3 subtotal lines and 2 duplicate rows removed.
• Check each duplicate. If one was a real second sale, tell Claude to put it back.
• One more change? Ask in plain words: "Highlight the top category in each month in light green." Claude adds a conditional formatting rule.

Check it in Excel

1. Open the download and click Enable Editing in Protected View.
2. Click one month's category total, like B4. The formula bar should show =SUMIFS(...), not a typed number.
3. Tie one month to the source: the export's July subtotal line was $900.75.