.XLSX File Extension
Zip-compressed XML spreadsheet format created by Microsoft Excel.
application/vnd.openxmlformats-officedocument.spreadsheetml.sheet
50 4B 03 04 (PK.. Zip archive)
Format Architecture & Technical Specifications
XLSX is the default file format for Microsoft Excel 2007 and newer. It stores numerical data, formulas, charts, pivot tables, and lookup tables organized across worksheet grids.
How to Open .XLSX Files
1 Open in Google Sheets
Drag .xlsx into Google Drive to edit spreadsheets online for free.
Compatible Software Programs
Microsoft Excel 365
windows, mac, android, ios • Commercial
Google Sheets
windows, mac, linux, android, ios • Free
LibreOffice Calc
windows, mac, linux • Free
Security Considerations & Verification
Standard XLSX spreadsheets do not store macros (XLSM stores macros). Safe.
- Extract xl/worksheets/sheet1.xml from renamed .zip archive to retrieve cell data values.
Frequently Asked Questions
What is a .XLSX file?
A .XLSX file is a Microsoft Excel Open XML Spreadsheet associated with Documents. Zip-compressed XML spreadsheet format created by Microsoft Excel.
How do I open a .XLSX file on Windows or Mac?
You can open .XLSX files using Microsoft Excel 365, Google Sheets, LibreOffice Calc. If you do not have native software installed, you can use AnyFileX's free File Identifier or convert .XLSX to a standard format in your browser.
Is a .XLSX file safe to open?
This format carries a safety rating of Low Risk. Standard XLSX spreadsheets do not store macros (XLSM stores macros). Safe.
Can I convert a .XLSX file to other formats?
Yes! .XLSX can be converted to formats such as .CSV, .PDF directly in your web browser.
What should I do if a .XLSX file is corrupted or won't open?
If your .XLSX file displays an invalid header or signature error, check its magic bytes hex header (50 4B 03 04 (PK.. Zip archive)) using AnyFileX's Magic Byte Detector or follow our step-by-step file repair guide.