How to Check if VBA is Running in 64-bit Mode

This simple function will tell you whether the current VBA code is executing in 64-bit mode or 32-bit mode.

Please note that this code is checking the VBA bitness, not the operating system bitness.  It is quite common for VBA to be running in 32-bit mode on a 64-bit Windows system.

While there are surely other uses for a function like this, I use it primarily as part of my automated error-logging routine.

The Code: As Function

'Returns True if the user is running 64-bit *VBA*
'   This is *NOT* the same as the Windows bitness;
'   64-bit Windows can (and often does) run 32-bit VBA
Public Function Is64bitVba() As Boolean
    #If Win64 Then
        Is64bitVba = True
    #End If
End Function

The function makes use of the Win64 compiler constant.  That constant did not get introduced until VBA 7 (Access 2010).  However, the above code will still work in earlier versions of VBA because unrecognized compiler constants evaluate to False.

The Code: As Class Property

In my own code, I actually use Is64bitVba as a property within my global singleton class, clsApp.

'Returns True if the user is running 64-bit *VBA*
'   This is *NOT* the same as the Windows bitness;
'   64-bit Windows can (and often does) run 32-bit VBA
Public Property Get Is64bitVba() As Boolean
    #If Win64 Then
        Is64bitVba = True
    #End If
End Property

Here are the two approaches in action from the Immediate window:

External references

Compiler constants (VBA)

Office VBA reference topic

Microsoft Docso365devx

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