Excel to CSV & CSV to Excel — Free, No Upload
Drop an Excel file to get CSV, or drop a CSV to get a real .xlsx workbook. Multi-sheet workbooks included — nothing is uploaded, ever.
Excel ↔ CSV
XLSX / XLS / CSV — both directions, every sheet
How it works
Both directions use the same rules the spreadsheet apps use: headers stay on row one, quoted fields keep their commas, and an empty workbook never becomes a full of stray columns. For Excel → CSV you can switch between sheets without re-uploading, and the output you see is byte-for-byte the file you download.
Why it's private
Spreadsheets are where real data lives — customer lists, payroll exports, order history. Converting an XLSX to CSV on a "free" online tool means handing that sheet to a stranger's server for no reason. Here the workbook is opened and rewritten inside your browser tab; the file never crosses your network, and when the tab closes there is no trace of it on any server.
Who needs this
Analysts moving between Excel and pipelines that only eat CSV, developers normalising client-provided .xlsx files before an API, and anyone cleaning up a multi-sheet workbook without re-typing a single row.