Convert an Excel worksheet to CSV safely

Step-by-step approach

Make a copy of the workbook and identify which worksheet contains the data.
Check whether cells contain formulas, dates or leading-zero identifiers that require special attention.
Use XLSX Sheet to CSV and select the exact sheet name if needed.
Review row and column counts; formulas are not executed and cached values may be stale.
Import the downloaded CSV as text when exact identifiers and dates matter.

Try the matching tool

Open XLSX Sheet to CSV to work on a local copy. Review the result before importing it elsewhere.

What this does not solve

Browser tools can validate known structures and transform available data, but cannot restore deleted or corrupted bytes, infer unknown business facts, or guarantee that a target system will import every field as intended.