.XLSB File Extension

Microsoft Excel Binary Spreadsheet

Developer Microsoft
3.7  |  102 Votes

What is an XLSB file?

An XLSB file is a spreadsheet workbook created by Microsoft Excel, a program used to create and edit spreadsheets. It contains one or more spreadsheets with cells arranged by a grid of rows and columns, and may include charts, graphs, and formatting. XLSB files are saved in a binary format.

More Information

Screenshot of a .xlsb file in Microsoft Excel 365
XLSB file open in Microsoft Excel 365

XLSB files differ from standard Open XML format (.XLSX) spreadsheets since they store the spreadsheet using a binary format (BIFF12). You will most likely see and use the XLSX file more often because it is compressed to save space and is easier to share with other users. XLSB files are not compressed, making them larger than XLSX files. However, XLSB files may perform more efficiently within Excel because they are saved in the larger binary format.

To create an XLSB file with Excel, select File → Save As, then select "Excel Binary Workbook (*.xlsb)" from the file type dropdown menu. Depending on the operating system you are using, Excel saves XLSB files in the following locations by default:

Windows Vista, 7, & 10:
C:\​Users\​<user name>\​AppData\​Local\​Microsoft\​Excel\​XLStart

Windows XP:
C:\​Documents and Settings\​Application Data\​Microsoft\​Excel\​XLStart

~/​Library/​Containers/​com.microsoft.Excel/​Data/​Library/​Application Support/​Microsoft/​Roaming/​Excel/​

How to open an XLSB file

You can open XLSB files with Microsoft Excel in Windows and macOS. You can also open XLSB files with OpenOffice Calc (multiplatform).

However, Excel is the best option for opening XLSB files because it fully supports the formatting of Excel spreadsheets, which may include graphs and the spacing of data fields. To open an XLSB file with Excel, select File → Open → Browse, then choose the XLSB file you would like to open.

How to convert an XLSB file

Microsoft Excel can convert XLSB files to various formats. In the Windows and Mac versions, select File → Save As and choose one of the following formats:

  • .XLSX - Microsoft Excel Spreadsheet
  • .XLS - Microsoft Excel Spreadsheet (Legacy)
  • .ODS - OpenDocument Spreadsheet
  • .CSV - Comma-Separated Values
  • .DIF - Data Interchange Format
  • .PDF - Portable Document Format
  • .XPS - XML Paper Specification (Windows only)
  • .RTF - Rich Text Format
  • .TXT - Plain Text
  • .HTM, .HTML - HTML Webpage
  • .XML - Extensible Markup Language
  • .MHT, .MHTML - MIME HTML Archive


XLSB files are typically legitimate spreadsheets, but cybercriminals may also use them for distributing and executing malware attacks on victims' computers. For example, QakBot malware may embed macros in XLSB spreadsheets that run when a user opens an XLSB file attached to an email. To protect against malicious Windows attacks, never open an XLSB file from the Internet unless you can verify the source's legitimacy.

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