What is a .XLSX file?
XLSX is the modern Microsoft Excel spreadsheet format, stored as a zipped XML package.
- Did you know
- XLSX became Excel’s default format with Microsoft Office 2007, replacing the old .xls.
- An XLSX worksheet is limited to 1,048,576 rows and 16,384 columns, the powers of two 2^20 and 2^14.
- The format’s internal SpreadsheetML markup was standardised as ECMA-376 and later as ISO/IEC 29500.
- The standard comes in two flavours, “Transitional” and “Strict”, the latter dropping legacy features kept only for converting old binary files.
- Under the hood a .XLSX file is really a ZIP archive - rename it to .zip and you can browse the files inside.
- What Analyser shows you
- Open and read Microsoft Office documents - modern Word, Excel and PowerPoint (DOCX, XLSX, PPTX), their template, macro-enabled and slideshow variants (DOTX, XLTX, POTX, DOCM, XLSM, PPTM, PPSX), and the legacy 97-2003 binaries (DOC, XLS, PPT) - plus the OpenDocument family in every shape: zipped and flat single-XML text, spreadsheets, presentations and graphics (ODT, ODS, ODP, ODG, FODT, FODS), templates (OTT, OTS, OTP, OTG), legacy StarOffice (SXW, SXC, SXD), and EPUB e-books, shown as page previews with selectable text, tables, sheets and slides.
- Open a .XLSX file
- Drag a .XLSX file onto the Analyser home page (or tap to pick one). It opens entirely in your browser - nothing is uploaded, there is no account, and it works offline once installed.