How to check if DLL is compiled as 32-bit or 64-bit? November 30, 2011 by Muhammad Jawaid Shamshadin C/C++, Microsoft, Technology, WindowsLeave a Comment on How to check if DLL is compiled as 32-bit or 64-bit? Open visual studio command prompt Use this command: dumpbin /headers C:\path\name.dll at the very beginning you will find “FILE HEADER VALUES”, the first value will have a “(x86) ” for 32 bit and “(x64)” for 64 bit. 24.94622567.04707