Excel spreadsheets are commonly used to store small or large sized data conveniently. Moreover, you can visualize the spreadsheet data and perform differnet operations to manipulate it. XLS was the earlier file format that was used by Microsoft Excel to store spreadsheet data. Although Microsoft introduced XLSX in 2007 with extended features and capabilities, various people still use XLS format that you have to convert to XLSX afterwards. In this article, you will learn how to convert XLS files to XLSX format programmatically in Python.