Spreadsheets are where private data lives
Client lists, salaries, budgets, experiment results โ the average spreadsheet is exactly the file you should never feed to a random "free online converter" with a server behind it. Here the workbook is parsed by your own browser: every sheet becomes a separate CSV or JSON file, and multi-sheet workbooks come down as a single ZIP.
The CSV comes out UTF-8 with a BOM โ the small detail that makes Excel itself reopen the file with correct accents and Cyrillic instead of mojibake. The JSON mode outputs an array of row objects keyed by your header row, ready to paste into code.
Frequently asked questions
How are multiple sheets handled?
Each sheet becomes its own file, named after the workbook and the sheet. When there is more than one, a single ZIP with everything is offered too.
Will dates and formulas survive?
Cell values are exported โ formulas are replaced by their computed results, and dates come out in a readable form. Formatting, colors and charts are not part of CSV by design.
Does it work with password-protected files?
No โ encrypted workbooks cannot be opened. Remove the password in your spreadsheet app first.