This article explains what XLSX files are, how to open them, and which programs are able to convert them to other spreadsheet formats like CSV or ODS.

If you cannot open an Excel file and see Excel cannot open the file because the file format or extension is not valid error, see this post.

Want to convert an Excel file (XLSX or XLS) to GPX format on Windows 11/10? Checkout a free software and online tool to do that.