What is an XLA file? An XLA file is an add-in used by Microsoft Excel, a spreadsheet application included in the Microsoft Office suite. It is used to add additional commands and features to Excel. Some XLA files are developed by Microsoft, while others are created by third-party developers and Excel users.

More Information Because different users use Microsoft Excel for different, specialized tasks, Microsoft allows users to add additional features to Excel. To add these features, users must install an Excell add-in, which is stored in an XLA file. Some XLA files, such as the Solver and Analysis ToolPak add-ins, come pre-installed with Excel. To activate these add-ins: Select File → Options → Add-Ins . In the Manage window, select Excel Add-ins → Go . In the Add-Ins available window, select the add-ins you want to activate. Click OK . Users can install additional add-ins by downloading or creating their own XLA files and then manually adding those files to Excel.