XLSX — Microsoft Excel Workbook
XLSX is the default format of Microsoft Excel since 2007. Like DOCX, it's a ZIP container of XML files, and it's an open standard. An XLSX workbook holds one or more worksheets of cells, and each cell can contain values, formulas, formatting, validation rules and more.
Beyond the grid, workbooks can hold charts, pivot tables, images and named ranges — a complete data-analysis document.
What Excel (XLSX) files are used for
- Financial models, budgets and reports
- Data analysis and dashboards
- Anything humans read, sort, filter and annotate as a table
Advantages
- Formulas, formatting and multiple sheets in one file
- Opens in Excel, Google Sheets and LibreOffice Calc
- Preserves data types — dates, currencies, percentages
Limitations
- Overkill for machine-to-machine data exchange — that's CSV's job
- Databases and scripts generally can't ingest XLSX directly
- Macros (in the XLSM variant) are a common malware vector — plain XLSX is safer
How to open a Excel (XLSX) file
Microsoft Excel, Google Sheets (free, browser-based) and LibreOffice Calc (free, desktop) all open XLSX. To feed the data into a database, script or import form, convert the workbook to CSV.