Why convert Excel files to CSV?
Excel's .xlsx format is great for human-edited spreadsheets — formulas, multiple sheets, charts, formatting — but it's a poor fit for data exchange between systems. Databases, ETL pipelines, command-line tools, and most APIs expect CSV: plain text, comma-separated, one row per line. Converting from XLSX to CSV strips away the Excel-specific layer and produces a portable file any system can read.
The tool uses SheetJS (the most widely used JavaScript spreadsheet library) to parse Excel files entirely in your browser. No upload, no server, no waiting. Date cells are automatically formatted as ISO strings (YYYY-MM-DD) — the most database-friendly format. Multi-sheet workbooks are supported: pick any sheet from the picker after the first conversion.