XLSX is a spreadsheet document file generated by Microsoft Excel software. XLSX file stores various types of data in cells. XLSX files can also contain graphs, mathematical formulas, styles, and formatting.

Organized layout

XLSX file format uses tables to a means of organizing, analyzing and storing data. A table is composed of cells (each individual cell can have unique formatting) organized in rows and columns creating a spreadsheets that in turn create a larger structure called worksheet.

XLSX open format

XLSX spreadsheet combines Open XML architecture with and ZIP archive for smaller files sizes and easier file management. In effect, an XLSX file is a ZIP archive composed of many smaller XML files. Microsoft developed the open XLSX format as a direct result of competitive pressure from Open Office and its Open Document Format (ODF). Although XLSX and ODF both are based on Open XML standard, they differ in various key aspects.

XLSX as the successor to XLS

XLSX was introduced along with Microsoft Office 2007 effectively replacing the older XLS format, which was until then considered the most popular format for spreadsheet documents.