XLSX
Microsoft Excel Open XML Spreadsheet
MIME type: application/vnd.openxmlformats-officedocument.spreadsheetml.sheet
XLSX is the default file format for Microsoft Excel spreadsheets since Office 2007. It stores data, formulas, charts, and formatting in a ZIP-compressed XML container.
Advantages
- +Industry standard for spreadsheets
- +Supports formulas, charts, macros
- +Smaller than XLS (ZIP compressed)
- +Compatible with Google Sheets, LibreOffice
Limitations
- -Binary content can be hard to diff/merge
- -Macro-enabled versions (.xlsm) can be security risks
- -Complex for simple data (use CSV instead)
- -Proprietary format specification
Common Use Cases
Technical Details
XLSX files are ZIP archives containing XML files. Worksheet data is in xl/worksheets/sheet1.xml with shared strings in xl/sharedStrings.xml. Cell values, formulas, and formatting are stored separately for efficiency.
Frequently Asked Questions
What is an XLSX file?
XLSX is Microsoft Excel's default spreadsheet format since 2007. It's a ZIP archive containing XML files with your data, formulas, charts, and formatting.
How do I convert XLSX to CSV?
Open the file in Excel or Google Sheets and export as CSV. For bulk conversion, use BriskTool's conversion tools.