How to determine whether a computer is running a 32-bit version or 64-bit version of the Windows operating system

Applies to: Microsoft Windows XP ProfessionalMicrosoft Windows XP Tablet PC EditionMicrosoft Windows XP Home Edition More

To continue receiving security updates for Windows, make sure that you're running Windows XP with Service Pack 3 (SP3). For more information, refer to this Microsoft webpage: Support is ending for some versions of Windows


This article automatically determines whether a computer is running a 32-bit or 64-bit version of Windows. This article also describes how to manually determine whether a computer is running a 32-bit or 64-bit version of Windows. Generally, a computer's bit count indicates how much data it can process, the speed with which it can process the data, and the maximum memory capacity. In order to optimize the computer's performance, the bit count of the operating system that is installed on the computer should match the bit count of the computer itself.

Determine which version of Windows is installed

Use the following methods to determine which version of Windows is installed, as appropriate for the operating system that you are running. 

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  • To find the computer’s bit count, see the documentation that was included with the computer or contact the hardware manufacturer.
  • Intel Itanium-based computers can run only 64-bit versions of Windows. Intel Itanium-based computers cannot run 32-bit versions of Windows. Currently, 64-bit versions of Windows run only on Itanium-based computers and on AMD64-based computers.


If you cannot use these methods to determine the operating system bit count, unfortunately this article can't help you any further. As a next step, you might want to ask someone that you know for help, or you might want to contact Support. For information about how to contact Support, go to the Microsoft Support website.

The third-party products that this article discusses are manufactured by companies that are independent of Microsoft. Microsoft makes no warranty, implied or otherwise, about the performance or reliability of these products.