During the TechEd 2012 keynote, Microsoft revealed a new edition of Office 15, or as it is now known as, Office 2013. This new edition, called Office 2013 RT edition, was demonstrated briefly at TechEd giving everyone a glimpse at how this new version of Office will work on Windows RT.
As you can see from the screenshot above, Excel 2013 looks pretty good. Notice how the buttons are flatter and the user interface is cleaner than what we have seen from previous leaked screenshots. Details about Office 15 hit the internet a while back and newer builds of Office 15 or Office 2013 feature colored window shadows, faster animations, and a newer more refined look and feel to the interface, compared to the beta builds. Microsoft is looking for a 2013 release for Office 2013 and Office 2013 RT is expected to be bundled with Windows RT when it gets released.