CSV to XLS Converter allows you to convert your csv (comma-separated value) files to Excel database (.XLS or XLSX). Microsoft Excel is a spreadsheet application developed by Microsoft for Microsoft Windows and Mac OS. MS Excel up until 2007 version used a proprietary binary file format called Binary Interchange File Format (BIFF) as its primary format. Excel 2007 uses Office Open XML as its primary file format. XLS is a wide-used format, many programs allow saving information in XLS format. It is very convenient and Microsoft Excel provides many possibilities for information management. On the ‘Options’ tab you can define a delimiter, such as TAB, semicolon etc. CSV to XLS Converter allows you to transfer your csv files to XLS or XLSX formats quickly and easily.