XLSX (Microsoft Excel Spreadsheet)

The XLSX file format was developed by Microsoft for its 2010 version of the Microsoft Office Excel spreadsheet application. It is an XML file-based format wrapped in a compressed ZIP file and is the successor to the older legacy binary XLS format.

XLSX spreadsheet files have over time become the standard format for editing and storing spreadsheet data, and although developed for the Microsoft Office suite of programs, the XLSX format can be opened by many third-party programs and remains the most well-known spreadsheet format today.