Microsoft Office Tutorials and References
In Depth Information
The Excel File Format
• It’s extensible . The .xlsx format uses XML (the eXtensible Markup Language),
which is a standardized way to store information. XML storage doesn’t benefit
the average person, but it’s sure to earn a lot of love from companies that plan to
build custom software that uses Excel documents. As long as Excel documents
are stored in XML, these companies can create automated programs that pull
the information they need straight out of a spreadsheet, without going through
Excel. These programs can also generate made-to-measure Excel documents all
on their own.
For all these reasons, .xlsx is the format of choice for Excel 2010. However, Microsoft
prefers to give people all the choices they could ever need (rather than make life
really simple), and Excel file formats are no exception. In fact, the .xlsx file format
actually has two additional flavors.
First, there’s the closely related .xls m cousin, which adds the ability to store macro
code. If you’ve added any macros to your spreadsheet, Excel prompts you to use this
file type when you save your spreadsheet.
Second, there’s the optimized .xls b format, which is a specialized option that just
might be faster when you’re opening and saving gargantuan spreadsheets. The .xlsb
format has the same automatic compression and error-resistance as .xlsx, but it
doesn’t use XML. Instead, it stores information in raw binary form (good ol’ ones
and zeroes), which is speedier in some situations. To use the .xlsb format, choose
File ➝ Save As, and then, from the “Save as type” list, choose Excel Binary Workbook
poWer Users’ CliniC
Under the Hood with .xlsx Files
Here’s a shocking secret: The new .xlsx file format is
actually a Zip file in disguise. It’s composed of several files that
are compressed and then packaged together as a single
unit. With a little know-how, you can take a look at these
hidden files-within-a-file, which makes for a great Excel
party trick. Here’s how:
1. Save your Excel spreadsheet in .xlsx format.
2. Browse to the file (using My Computer, Windows
Explorer, or your favorite file management tool). If
you’re lazy, you can save the file on the desktop so
you can manipulate it right there.
3. Right-click the file, and then choose Rename.
4. Change the file extension to .zip. So if you start with
BlackMarketDinnerware.xlsx, change it to
5. Now, open the Zip file by double-clicking the file.
6. You can now see the files that are hidden inside
your Excel file. They’re organized into several
folders (Figure 14-17). To find the actual content from
your spreadsheet, head to xl➝worksheets➝sheet1.
xml. Double-click it to open it up and take a look at
7. When you’re finished, rename the file using its .xlsx
extension so you can open it in Excel.
To learn way more about the technical details of this type
of file storage, you can read the Microsoft white paper at