Compare Two Excel Workbooks
Choose a reliable method based on what “different” means.
What this solves
Compare an old and new inventory snapshot. This pattern is useful when the business question is clear but a generic tutorial is too abstract.
The rule
Define the key first, then compare selected fields, missing keys and duplicates separately.
Key: SKU · Compare: Qty, Price, StatusGoogle Sheets: The core pattern is also usable in Google Sheets; exact function support and locale separators can differ.
Real-work checklist
- Define the business key and expected grain before writing the formula, query or markup.
- Test the pattern on a small known sample where you can verify the answer manually.
- Check missing values, duplicates and data types before trusting a large result.
- Scale to the real file or database only after the logic is proven.
Common mistake
Cell-by-cell comparison can report noise when rows have been reordered.