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This is undoubtedly a duplicate question, but my search skills have failed me.

How can I determine whether an app is 64-bit or 32-bit on Windows?

Ideally, I'd like to be able to do this on both 64-bit Windows XP and 64-bit Windows 7.


EDIT: thanks for the responses. Is there a way I can do this when the app is not running? For example, on Linux we've got "readelf"--a command line util to inspect binaries. Is there a comparable tool on Windows?

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up vote 11 down vote accepted

On x64 platform, in Windows Task Manager, 32-bit applications will have "*32" appended to their names. So:

firefox.exe *32
devenv.exe *32

means that both Firefox and Visual Studio are 32-bit applications, whereas Windows Services Host is a 64-bit app.

On x86 platform, it's easy: 64-bit applications won't start.

To reply to your last edit, I don't think there is a tool shipped with Windows which does detect if an executable is a x64 or x86. Maybe third-party tools can do it (decompilers? ressource extractors?).

If you are a developer, you can also consider doing such a tool or use Visual Studio corflags. See an answer on StackOverflow for more details.

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DAMN just beat me..... +1! – Campo Jul 20 '10 at 16:53
Thanks for the info! +1 – Tom Sep 8 '10 at 17:39

start taskmanager and look at the processes tab

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