Upload your file
Private by default
Conversion happens entirely in your browser. Your file is never uploaded, stored, or seen by anyone else.
Any direction
CSV → Excel (.xlsx) or Excel → CSV. We auto-detect your input and pick the opposite format.
No signup, no limits
Free forever. No watermarks, no email required, no daily caps. Just drop a file and get the output.
Questions people ask
Is this really free?
Yes. No account, no payment, no watermark. The tool runs in your browser using open-source libraries.
Do you upload my file to a server?
No. The file never leaves your device. All parsing and conversion happens locally in JavaScript.
Which Excel formats do you support?
Reading: .xlsx and legacy .xls. Writing: .xlsx (modern Excel, works in Excel, Numbers, Google Sheets, LibreOffice).
What about multi-sheet Excel files?
When converting Excel to CSV, we export the first sheet. For multi-sheet workbooks, open the file in Excel and export each sheet separately if you need all of them.
What is the file-size limit?
Browser memory is the only limit. Files up to ~50 MB generally work fine on modern laptops. Very large CSVs may be slow — try splitting them first.
Does it handle semicolons, tabs, or commas?
Yes. The CSV parser auto-detects common delimiters (comma, semicolon, tab) and handles quoted fields and UTF-8 correctly.