Find the Best Key Column in a Spreadsheet

What this tool does

Choosing the wrong key can make a reconciliation appear successful while joining unrelated records. Key Column Finder examines each column’s non-blank rate and normalized uniqueness, then combines those measures into an explainable score. A nearly complete, fully unique identifier such as Employee Code or Invoice Number usually ranks above names, departments or statuses. The recommendation is a data-quality signal rather than a business guarantee, and the result explicitly identifies columns that may be better suited as one part of a future composite key.

How to use it

1. Upload the dataset.
2. Review columns sorted by key score.
3. Confirm the top candidate with the data owner and inspect duplicate or blank values before matching.

Limitations and review points

A technically unique column may still be an unstable key, such as a row number generated during export. Business ownership and persistence must be confirmed separately.