andreworia/data-cleaning-for-excel

Data Cleaning for Excel

When to use

Use this immediately after pasting or importing raw data, a CSV export, a copy from another system, or a table copied out of a document, before you build a pivot table or a formula on top of it.

Instructions

1. Identify inconsistent formats within the same column (text numbers next to real numbers, mixed date formats, inconsistent casing).
2. Remove or flag exact duplicate rows, stating the rule used to define a duplicate.
3. Standardize blank cells: distinguish a true zero from a missing value and handle each consistently.
4. Trim stray whitespace and normalize inconsistent category labels that clearly refer to the same thing.
5. Convert text-formatted numbers and dates to their proper Excel types so formulas can use them.
6. Report what was changed, row by row where practical, so the cleaning is auditable.

Example prompts

• "Use the data-cleaning-for-excel skill on this pasted CSV before I pivot it."
• "Clean up this exported customer list, the dates are in three different formats."

Output

A cleaned, consistently formatted range, plus a short change log describing what was standardized, removed, or converted.