XLS vs XLSX - XLS Viewer & Converter

Excel Document Types and the New File Format

What is XLS file format? XLS is the default extension for created in previous versions of Excel 2007. It have an .xls extension. When these files are opened in Excel 2007, Excel opens in Compatibility mode. In this mode, you can make changes to documents and use the new features. When you save a file in this format, the Compatibility Checker runs, and a list of incompatible features is shown.

The tables set up in the active file are not displayed in the previous version. After the Compatibility Checker has run, you can either save the file anyway, in which case the incompatible features are disabled, or you can cancel the save operation and use the Save As command to save the file as an XLSX file, to retain its full format and function.

What is XLSX file format? XLSX is the default format for files created in Excel 2007. You can use this file format throughout the majority of this book. An XLSX file is a special kind of compressed file that contains all the data, document formatting, and formulas in one compressed file. One interesting thing about the new format is that what appears to be a single file is actually a compressed set of files. You can uncompress this file with Windows XP or Windows Vista to see what the internal structure of the file looks like. The data in the file is all the same — the only difference between the files is the way they have been saved.

Although you do not work with the XML directly while learning to use Excel, it is useful to be familiar with the pieces of the files that are stored within the XLSX compressed file. Spend a few minutes browsing through the folder with the uncompressed file information.

What is XLSM file format? XLSM is another change Microsoft made with Excel 2007 is to split the basic format of files into two types. XLSM, is used to store any Excel spreadsheet that has macros. Macros are programs that help you do work better, cleaner, and more efficiently. A file with the extension .xlsx cannot have any code attached to it. If you are storing a file with code in Excel 2007 format, the code must go into a file whose extension ends with the letter m rather than the letter x.

Why make this differentiation? For security reasons. In the past, lots of viruses were distributed as macros hidden in seemingly harmless documents. Merely opening the document would run the virus code and spread it to all other documents on the computer. With this new setup, the potential for spreading viruses through regular Excel files is minimized.

If you receive an XLSX file by e-mail, you know that the file does not have any code included. If you receive an XLSM file, you know that code may be attached to the file and you need to decide whether to trust the code. If you receive a file with the .xlsm extension from someone you do not know, you can tell Excel not to enable the macros.

What is XLSB file format? In addition to the XML-based file types developed for Excel 2007, Microsoft created a new binary format for this version. The new binary format, whose extension is .xlsb, was created to provide a way for Excel users to store extremely large files. XLSB files are set up to be slightly smaller and considerably more efficient to open and run. Unless you are creating very large files, you are not likely to create XLSB files.

Differences between Excel (.xls) files and Excel (.xlsx) files.

For many years, Excel has saved regular spreadsheets with the ".xls" extension.This has changed with Excel 2007, which now saves regular spreadsheets with the ".xlsx" extension. What does this mean?

• The big difference between a .xls & .xlsx is anyone can open, edit and save a spreadsheet with the .xls extension (otherwise known as Excel 97-2003 format).
• To open spreadsheets with a ".xlsx" extension, users with older versions of Excel will have to download the compatibility application patch from Microsoft. This patch will work for Excel 2000 and up.

Can I open my spreadsheet from previous versions of Excel in Excel 2007?

Compatibility Issues. When opening an older version of an Excel spreadsheet (97 – 2003) in Excel 2007, you will be put into Compatibility Mode. That means:

a. You will see [Compatibility Mode] next to the title of your paper in the title bar.
b. You may not have access to the new features that have been built into Excel 2007, such as:

• New Table Styles: Light, Medium, and Dark.
• New Cell Styles: Good, Bad, Neutral; Data and Model; Themed Cell Styles (Accent Styles)
• New Conditional formatting: Top/Bottom Rules, Data Bars, Color Scales, Icon sets Rules.
• New drawing objects: SmartArt objects
• Anything that was added to Excel 2007 may not be accessible in Compatibility mode.

c. The spreadsheet may be sent to anybody having almost any version of Excel (including Excel 2007).