What is a .XLSX file?
.xlsx is an Excel workbook format used in Excel versions 2007 onwards without the VBA macros functionality. This format is mainly composed of the Office Open XML SpreadsheetML, which is a ZIP package containing the following XML parts: worksheets, workbook relationships, styles, shared strings, themes, charts, drawings, and metadata. Microsoft developed this format in Office Open XML while Ecma standardized it to ECMA-376 and ISO/IEC standardized it as ISO/IEC 29500.
This format is generally viewed as business reports, budgets, data tables, invoices, data from web system exportations, analytics downloaded files and shared spreadsheet templates. The two types of this related workbook formats using this extension include the OOXML Transitional, the default Excel output and OOXML Strict, the stricter ISO variant with a different namespace and no older compatibility features.
OOXML Transitional and OOXML Strict are generally seen as ZIP files at the binary level and beginning with PK bytes. These two formats can only be distinguished through their respective packages and content types found in the [Content_Types].xml and SpreadsheetML namespaces respectively. .xlsx files are not supposed to store the VBA macros by design since macro enabled workbooks use .xlsm and binary Excel uses the .xlsb format. A wide range of applications can view this format but current Excel provides the best calculation and rendering capabilities.
How to open a .XLSX file
Open a .XLSX file on Windows
- 1 Go to the folder with your file in File Explorer. Usually, downloaded files end up in Downloads.
- 2 Double-click your .XLSX file if you have an app for .xlsx files on your computer. In case it does not open, move on to step three.
- 3 Right-click your .XLSX file -> select .
- 4 Choose Microsoft Excel in the list (Windows 11: choose Always). For Windows 10 -> put a check on "Always use this app to open .xlsx files" and click OK.
Still not opening? See common problems and fixes, or view it in your browser.
Programs for Windows
- Microsoft Excel paid
- LibreOffice Calc open-source
- ONLYOFFICE Docs freemium
- WPS Spreadsheet freemium
- Apache OpenOffice Calc open-source
- Collabora Office paid
- SoftMaker PlanMaker paid
Open a .XLSX file on macOS
- 1 In the Finder app, locate your .XLSX file.
- 2 Just double-click your .XLSX file in order to automatically launch the program which is connected with it.
- 3 Need another app on your Mac? Control-click the file (or right-click with a mouse). In the pop-up menu select .
- 4 If it isn't in the list, choose and find the application manually.
Still not opening? See common problems and fixes, or view it in your browser.
Programs for macOS
- Microsoft Excel paid
- LibreOffice Calc open-source
- Apple Numbers free
- ONLYOFFICE Docs freemium
- WPS Spreadsheet freemium
- Apache OpenOffice Calc open-source
- Collabora Office paid
- SoftMaker PlanMaker paid
Open a .XLSX file on Linux
- 1 Launch your file manager. Depending on the desktop it may be named Files (GNOME), Dolphin (KDE Plasma), Nemo (Cinnamon) or Thunar (Xfce).
- 2 Double-click the file.
- 3 Or choose another program by right-clicking the file -> .
- 4 Install LibreOffice Calc (if it is not installed on your computer) from the software centre, repository or Flathub.
Still not opening? See common problems and fixes, or view it in your browser.
Programs for Linux
- LibreOffice Calc open-source
- ONLYOFFICE Docs freemium
- WPS Spreadsheet freemium
- Apache OpenOffice Calc open-source
- Collabora Office paid
- Gnumeric open-source
- SoftMaker PlanMaker paid
Open a .XLSX file on Android
- 1 Launch Files or another file management app.
- 2 In Downloads, find the .XLSX file and open it by tapping.
- 3 A list of apps capable of opening the file will be shown. Tap Microsoft Excel and press Always to permanently connect the file type with this app.
- 4 No apps able to open this file? Download Microsoft Excel from the Google Play Store.
Still not opening? See common problems and fixes, or view it in your browser.
Programs for Android
- Microsoft Excel paid
- Google Sheets freemium
- ONLYOFFICE Docs freemium
- WPS Spreadsheet freemium
- Collabora Office paid
- Zoho Sheet freemium
- SoftMaker PlanMaker paid
Open a .XLSX file on iPhone / iPad
- 1 Use the Files app and go to On My iPhone, iCloud Drive or Downloads.
- 2 Tap the .XLSX file you want to open.
- 3 If the file can be opened by a built-in iOS app (supported format), it opens automatically.
- 4 Touch and hold the file to get the context menu -> choose -> select Microsoft Excel from the list of apps.
- 5 If there is no such option, download the app first from the App Store and then tap the document again.
Still not opening? See common problems and fixes, or view it in your browser.
Programs for iPhone / iPad
- Microsoft Excel paid
- Google Sheets freemium
- Apple Numbers free
- ONLYOFFICE Docs freemium
- WPS Spreadsheet freemium
- Collabora Office paid
- Zoho Sheet freemium
- SoftMaker PlanMaker paid
Open a .XLSX file online
- 1 Move to the online viewer at the top of this page.
- 2 Drag the file there or select it, and its contents will appear in your browser tab. The file is not uploaded.
Still not opening? See common problems and fixes, or view it in your browser.
Programs for Online
- Microsoft Excel paid
- Google Sheets freemium
- Apple Numbers free
- ONLYOFFICE Docs freemium
- Zoho Sheet freemium
- Microsoft Excel Viewer alternatives via Office for the web freemium
More details about opening .XLSX files
In Windows OS, the highest .xlsx file compatibility among available applications belongs to Microsoft Excel concerning formulas, PivotTables, charts and protected workbooks. Other applications able to work with this format are LibreOffice Calc, ONLYOFFICE, WPS Spreadsheet, Apache OpenOffice Calc, and SoftMaker PlanMaker. In macOS, .xlsx files could be opened via Microsoft Excel and Apple Numbers application. Numbers is free on Apple products, although it might reduce Excel-specific objects when exporting or importing data into this format. In Linux, the default office solution supporting .xlsx file is LibreOffice Calc. Gnumeric is more lightweight solution good for numeric sheets. Also, there is ONLYOFFICE and WPS applications trying to reach more accurate Excel-like interface.
On Android and iOS operating systems, Microsoft Excel, Google Sheets, WPS Office, ONLYOFFICE, Collabora Office, Zoho Sheet and Apple Numbers on iOS support .xlsx files. Browser-based viewing of this format can be provided by Excel for the web, Google Sheets, Zoho Sheet, ONLYOFFICE Docs and iCloud Numbers. In case double-click does not help, use Open With feature or change associations of .xlsx files to some spreadsheet application. On locked-down systems, it is possible to upload .xlsx file to online file viewer or install LibreOffice. If an email attachment does not work, download it to your device and make sure that its extension is .xlsx and size is greater than zero bytes, then try Open and Repair function in Excel or LibreOffice. For password-protected workbooks, it is recommended to use Excel or other spreadsheet program with ability of OOXML encryption, because some viewers might interpret password-encrypted file as corrupt.
Technical details
The .xlsx file is an OPC package, or rather, a ZIP archive created according to the Open Packaging Conventions. Usually, the first local file header starts with the 50 4B 03 04 signature (ZIP file header indicator) with offset equal to 0, but some valid ZIP archives start with other ZIP records. The reliable identifiers of .xlsx file are the package parts: [Content_Types].xml file defines the content types of the package, and _rels/.rels - defines the top-level relationships. The workbook data are XML files, most likely, UTF-8 encoded, although UTF-16 can occur in XML parts. For example, the workbook holds sheets in the xl/worksheets/sheetN.xml and workbook structure in the xl/workbook.xml file. The shared strings, styles, theme are usually stored in xl/sharedStrings.xml, xl/styles.xml, xl/theme/ respectively, the charts in xl/charts/, the drawings in xl/drawings/, and the multimedia data are stored in xl/media/. Also, document properties may be contained in docProps/core.xml and docProps/app.xml, and the custom properties may be stored in the custom XML part.
Usually, the compression format is ZIP Deflate, which makes text-heavy spreadsheets much smaller than the size of the raw XML. Still, there are many situations when the file becomes huge because it contains embedded images, cached pivot table, many different strings, drawing objects. The modern .xlsx worksheets utilize Excel's grid with 1,048,576 rows and 16,384 columns that end with XFD. The registered MIME type is application/vnd.openxmlformats-officedocument.spreadsheetml.sheet; however, the web server can assign the same file the application/zip or application/octet-stream MIME type. The OOXML supports Transitional and Strict conformance class files; usually, current version of Excel creates Transitional .xlsx files and allows to open Strict files, but older non-Microsoft applications have various Strict files support. ISO/IEC 29500:2021 is the current edition of this format standard.
How to convert .XLSX files
Use .PDF output if fixed, uneditable representation is needed for viewing and printing. The conversion can be done either using Save As in Excel or via GUI or with "libreoffice --headless --convert-to pdf --outdir out workbook.xlsx" command in Calc when batch processing. Converting a document preserves pages' appearance, while formulas editing won't be possible anymore.
CSV can be used when importing data into databases/creating scripts or plain text sharing is needed. This kind of conversion can be carried out both using LibreOffice GUI and via libreoffice --headless --convert-to csv --outdir out workbook.xlsx. In CSV files only text of particular worksheet is saved. That means all the content on additional worksheets and formatting is lost; formulas become values visible as result, and chart objects are removed during saving.
Use ODS when creating or sending files for opening or viewing in LibreOffice application. Formulas need testing since functions' names in two programs are not quite the same. Conversion to .XLS should be done in case if old version of the software or another application is required, since XLS format has more restricted rows and columns, and most of current Excel features are not available. HTML can be created in order to represent table on websites. Pivot table, formulas editing, comments and exact page representation are usually lost in that format. Google Sheets also can save files in these file formats.
| Convert to | Tool | Command / note |
|---|---|---|
| CSV | LibreOffice | libreoffice --headless --convert-to csv --outdir out workbook.xlsx Exports the active or first sheet by default; formulas become displayed values and formatting, charts, merged-cell layout, and extra sheets are not preserved in a single CSV. |
| LibreOffice | libreoffice --headless --convert-to pdf --outdir out workbook.xlsx Good for printing or sharing a fixed view; formulas are not editable and pagination depends on sheet print settings, fonts, and page size. |
|
| ODS | LibreOffice | libreoffice --headless --convert-to ods --outdir out workbook.xlsx Converts to OpenDocument Spreadsheet; most cell data and formulas transfer, but some Excel-specific functions, tables, slicers, and formatting may change. |
| HTML | LibreOffice | libreoffice --headless --convert-to html --outdir out workbook.xlsx Creates web-viewable tables; workbook features such as pivot tables, formulas, comments, and complex styling may be flattened or omitted. |
| XLS | Microsoft Excel or LibreOffice | libreoffice --headless --convert-to xls --outdir out workbook.xlsx Useful for older Excel versions; XLS has lower row and column limits and weaker support for modern Excel features. |
| XLSX from CSV | LibreOffice | libreoffice --headless --convert-to xlsx --outdir out data.csv Creates a workbook from delimited text; data typing, delimiter detection, dates, and leading zeros should be checked. |
Common problems and fixes
For "We found a problem with some content" error message, there is corrupt XML code within the ZIP file, issues in relationship files, or external link objects in the file. Solution for this error includes going to , selecting the file, clicking the drop down button beside open and then selecting Open and Repair. When the above fails, the user should try renaming the file from .xlsx to .zip file and then view the contents in the xl/ and _rels/ folders. The user should then compare the XML code with a good workbook's XML code. At times, the damaged file might open on LibreOffice Calc and the recovered sheets and/or cell values should be saved into a new .xlsx file.
An "Excel cannot open the file because the file format or file extension is not valid" message pops up if the file has been renamed improperly, partially downloaded during transfer, been blocked by e-mail software, encrypted, or if the file is not an OOXML workbook.
For "The default application to open this type of file is unknown" message, the default file association should be reset, or the user should access the app and check Always use this app checkbox for future use. A read-only mode occurs in case the file is flagged for final, located in a restricted folder, has Mark of the Web security header, being used by someone else, or if the file is OneDrive/SharePoint-synched workbook. When prompted for a password, the workbook or package has been encrypted, or worksheet/workbook protection is enabled but not for encryption. Warnings will arise when using external link since the formula refers to the other workbook/data source, therefore, the links can only be updated if the user can trust on such sources. Absence of fonts, printer driver, or locale information could alter pagination, labels in charts, numbers format, and date format.
Security considerations
The .xlsx file is not supposed to have the capability to contain a VBA macro project, and macro-enabled workbooks have either .xlsm or .xlsb extensions. Hence, a file being labeled as “macro-enabled .xlsx” might not only be a malicious one but also incorrectly saved file too. Without any use of VBA macros, it still can have some additional functionality like external references, OLE or embedded objects, data connections, web queries, old-school DDE formula and some other components which would lead to application errors. Formula injection should be considered while exporting to the CSV format or reading untrusted workbook, because some characters at the beginning of the cell like =, +, - or @ could be interpreted as formula in some spreadsheet programs. There were security vulnerabilities in XLSX parsing due to the ZIP+XML nature of the file format, and therefore updating Excel, LibreOffice, and mobile office software is necessary. Use Protected View mode for files received by email or from the web and never allow modification of the file unless the sender and purpose are trusted.
History and versions
.xlsx is an Open XML standard extension used for default Excel workbook format in Office 2007, instead of previous .xls. The .xlsx file format was designed in conjunction with a project initiated by Microsoft known as the Office Open XML Format project and became standardized as ECMA-376 in 2006 followed by International Organization for Standardization/International Electrotechnical Commission publication of the same standard in ISO/IEC 29500 in 2008, when it included the SpreadsheetML format together with Open Packaging Conventions model. The Office 2010 used this file format as de facto default format, improved standards conformability and continued use of the Transitional version in order to ensure maximum compatibility of old application software. The ability to open/save strictly-conformant Open XML files increased in Excel 2013.
It is actually used widely across Microsoft 365, also in data importing/exporting operations within Google Workspace environment, in some cases in LibreOffice spreadsheets and Apple's Numbers and even in a lot of corporate systems. Newer Office release brought even more functions and capabilities, supported by new versions of Excel software but might result in warnings on using them on old programs.
Related formats
.xls format denotes an older Excel binary workbook format. Its use should only be recommended where required by some legacy system because its capacity in terms of number of rows and columns is stricter and not all features in the current version of Excel can stand the round-trip test using .xls. .xlsm is the macro-enabled workbook in the OOXML format. This format is used where you have to save your document but preserve your macro too but note that macros add a risk element to your document because hackers use them to infect computers or steal your work or identity. .xlsb format is the binary format of Excel workbooks. .xlsb file can open much faster and can remain lighter compared to .xlsx file but it lacks transparency and support compared to its equivalent format. ODS is the OpenDocument Spreadsheet format used in software like LibreOffice etc. .csv and TSV are formats storing simple tabular data and are only good for importing or exporting purposes but they lose workbook format etc.
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