The PPTX Format

With Microsoft Office 2007, Microsoft introduced a new XML based file format called the Office Open XML (OOXML) document format. This new format is based on XML and has been adopted as an official standard for representing office documents like word processing files, spreadsheets, and presentations. These new files append an x to the end of the old Office file extensions, so PowerPoint files now have the .pptx extension. We read and write this format natively, which is why we give you the opportunity to download, email, and share presentations as PPTX files.

Compatibility

All new versions of Office read and write PPTX (and other OOXML formatted) files natively. This means Office 2007 and newer on the PC, and Office 2008 and newer on the Mac. For users without those programs, there are several alternatives:

PC Users

• Microsoft offers a free download: Microsoft Office Compatibility Pack for Office 2007 File Formats. This allows you to read and write Office 2007 files with earlier versions of Office.
• Microsoft PowerPoint Viewer 2007 is another free download from Microsoft that allows you to view PowerPoint documents without even needing to own any copy of Microsoft Office.

Mac Users

• The Microsoft Office Open XML File Format Converter is a free download that will convert PPTX files into the binary PPT Office format. This format can be read by older mac versions of office, or programs like Keynote and Open Office.

More Options

• Zamzar.com is a free service that lets you upload your PPTX document and then get that document emailed back to you in a number of other formats.