Windows RT Vs WinRT vs Windows 8


One of the things that I was confused about in the last few hours, and I am confident that many more people are going to be confused about in next few months is the difference between “Windows RT” and WinRT. Here is the simple version:

Windows RT:

  • It’s an OS.
  • It’s a variation of the Windows 8 OS that Microsoft has specifically designed for devices running ARM devics.
  • (In case you are wondering) ARM is an architecture used by many processor companies to design their chips, including Qualcomm, nVidia, Texas Instruments and several others.

What that means is that when you go to the Settings -> PC Info screen of a tablet device running an ARM processor, it will show you “Windows RT” and NOT “Windows 8”. So, it’s a full fledged OS that is branded and sold separately by Microsoft to tablet OEMs (aka manufacturers) who are using ARM processors in their tablet devices. Infact, it used to be called as “Windows on ARM” earlier but was later on re-branded as Windows RT.

You can see that it’s all part of the same make over. You better believe it – Microsoft is super serious about the Modern user experience!


  • It’s a runtime.
  • Conceptually, it’s not very differemt from .net, java or any other runtime in the sense that it’s main goal is to create a cross-platform application architecture on Windows 8 that supports multiple languages (C++, C#, JavaScript, etc).

Difference between “Windows RT” and “Windows 8”:

Now that we know that Windows RT is an OS, I am sure that some of you are wondering how is it different from Windows 8. Here it is!!

  • Not much different from user experience point of view as both support Metro UI.
  • Windows RT is not sold directly to consumers, and is meant only to be sold to device manufacturers (aka OEMs).
  • The goal behind Windows RT is to give end users consistent experience across tablets being offered by various manufacturers (including Microsoft’s own device called as Surface).  
  • Windows RT will come pre-pakaged with MS Office, whereas Windows 8 users will have to buy (and install) Office separately.
  • There are similar differences in terms of applications shipped out of the box in Windows RT and Winodws 8, as well as the kinds of applications you can develop/install/uninstall on them. Windows RT seems to be more locked-down version of the two.
  • You also cannot use Win32 and COM APIs on Windows RT, so you are pretty much restricted to using WinRT APIs. Although, over  next few days I am going to be closely working on a project that requires access to underlying System Information on a Windows RT “ARM” device. It seems that there may be a way to access a subset of Win 32 API on a Windows RT device. If it works, I will post my experience in a subsequent post.