ODS and XLS explained
ODS is the OpenDocument spreadsheet format, the open-standard counterpart to XLSX used by LibreOffice Calc.
The pre-2007 Excel format is a binary structure limited to 65,536 rows and 256 columns — limits modern datasets routinely exceed.
- Where ODS files come from
- LibreOffice Calc and open-standards environments.
- Where XLS is used
- Spreadsheets from Excel 2003 or earlier, and some legacy export systems.