Office 32-bit or 64-bit – which version is installed?

How can you tell if 32-bit or 64-bit Office 2010 is installed?

If you start Office 2010 there’s no immediately obvious difference between 32-bit and 64-bit versions of the software. 64-bit is visually indistinguishable from the 32-bit cousin and for most people the technically differences don’t matter – Office 2010 runs the same.

But if you need to know, or as just curious, how can you tell which version is running?

To confirm what software is running go to the equivalent of the ‘About’ screen – under the new Backstage menu. Click on File | Help and again look for the magic phrase ’64-bit’.

Office 2010 - About for 64-bit version image from Office 32-bit or 64-bit - which version is installed? at

Registry Key

In addition there’s a registry key you can search for programmatically or as a network administrator. The Office 2010 installer will add this key, if Outlook is included in the installation.

HKEY_LOCAL_MACHINESoftware MicrosoftOffice14.0Outlook

A key called ‘Bitness’ will be set as either x86 or x64

Outlook 2010 - Bitness registry key image from Office 32-bit or 64-bit - which version is installed? at

No, we don’t know why this useful indicator is only set for Outlook and not Office generally.


For VBA programmers there are two conditional constants for the compiler to let you choose between 32 and 64 bit code options:

#if VBA7 then
- 64-bit code that’s specific to VBA 7
- Code for previous versions of Office/VBA
#end if
#if Win64 then
- 64-bit code only for 64-bit versions
- 32-bit code only for 32-bit versions
#end if

A common application of these conditionals is for different DECLARE statements.