Microsoft File Extension for Excel Binary Workbook file
Excel Binary Workbook (.xlsb) files store information in binary format instead of the Open XML format of standard Excel 2007+ workbooks. Since .xlsb files are binary, they can be read from and written to much faster, making them extremely useful for very large spreadsheets. They also tend to be smaller than their xlsx or xlsm counterparts.
Other types of files may also use the .xlsb file extension.
Questions using the xlsb tag are expected to relate to programming. For example, specific questions about programmatically opening or creating .xlsb files are encouraged.
