Understanding Excel’s Binary File Format (XLSB)


- by Puneet

In Excel, you can save a workbook as an XLSB, which differs from the other formats. And in this tutorial, we will learn about it (binary file format).


What is Binary Format (XLSB)?

An Excel Binary Format Workbook (File) saves data in a binary format, unlike XML, which other formats (like XLSX) use. The user interface of a binary file is the same as other files. You can use it in the same way you use other workbooks.

You can add and delete the worksheets, create charts, pivot tables, write formulas, and write codes.

Save a Workbook in a Binary Format (XLSB)

When you open the “SAVE AS” dialog box, from the “Save as type” drop-down, you can select the “Excel Binary Workbook”. And then save it the way you normally save a workbook.


As I said, one of the biggest differences between XLSX and XLSB is that it saves the data in the workbook in binary format.


In the above example, we have two workbooks with the same set of data (253000 cell entries). And the XLSX format has a size of 2427 KBs, and the binary format has a size of 1784 KBs.

Benefits of Using Binary Format Workbook

As discussed above, one of the best parts of using the binary format is the smaller file size than the normal XLSX format. But there are a few more benefits of using it:

  • Smaller File Size – Compared to the default Excel file format, it is almost 25% smaller.
  • Faster Loading – When you have smaller files, it’s easy to open and load them.


Like XLSM file format, which is the specific Excel file format to store or rum macros, XLSB can also store macros. With this, it increases a security concern if you get an XLSB file from other users and that file contains a macro.

Normally with XLSM, you are always aware that it can have macros; you can disable macros in the Excel application before opening it.

That is not the case with XLSB. If it contains a macro and you have macros enabled. It can run a macro automatically.

Then Should I Use XLSB?

The best use of XLSB is to store data in it. It can help you to hold a large set of data. And especially when you don’t need to work on the file.

The best combination of binary files is with the POWER QUERY. You can directly extract data from multiple binary (XLSB) files with the help of a power query.

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