CSV to Excel without the usual problems
Opening a CSV directly in Excel can mangle data: leading zeros in ZIP codes and IDs disappear, long numbers turn into scientific notation, and accented characters break. This converter builds a proper .xlsx file where plain numbers are stored as numbers but values like 00123 or 16-digit IDs stay exactly as written.
Excel to CSV
Switch to Excel → CSV and drop an .xlsx, .xls or .ods file. Every sheet is exported as its own CSV in UTF-8 with a byte-order mark, so it re-opens correctly in Excel and imports cleanly into databases and CRMs.
Delimiters
European exports often use semicolons. Auto-detect handles comma, semicolon, tab and pipe; you can also pick one manually.
FAQ
Is my spreadsheet uploaded?
No. Conversion uses the SheetJS library inside your browser.
Are formulas kept when exporting to CSV?
CSV can only hold values, so each cell's displayed value is exported.