Excel Spreadsheet — Microsoft Excel workbook based on Office Open XML.
Quick facts
What is .xlsx
A .xlsx file is a Excel Spreadsheet — Microsoft Excel workbook based on Office Open XML.
In the mime-db registry it maps to application/vnd.openxmlformats-officedocument.spreadsheetml.sheet, and it is marked as non-compressible. When serving .xlsx over HTTP, set the Content-Type header as shown in Developer info below.
Related entities: it maps to application/vnd.openxmlformats-officedocument.spreadsheetml.sheet — and is delivered over HTTP via the Content-Type header.
How to open .xlsx files
Developer info
When served over HTTP, responses should set the following header:
Content-Type: application/vnd.openxmlformats-officedocument.spreadsheetml.sheet
Common software that reads/writes .xlsx:
Relation chain
Related extensions
Related MIME types
Common uses
How to edit .xlsx files
How to create .xlsx files
Frequently asked questions
Common options include Microsoft Excel, LibreOffice, Google Sheets. You can also open many of these files with built-in viewers or a browser.
Create a new file in any text editor or the app that owns the format and save it with the .xlsx extension.
application/vnd.openxmlformats-officedocument.spreadsheetml.sheet is the media type identifier used for .xlsx files during network transfer (for example in the HTTP Content-Type header).
Sources & standards
Updated 2026-08-18
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