Windows Portable Executable: determine if 32 or 64 bit

A Windows Portable Executable (EXE or DLL) is (nowadays) either compiled for execution in 32 or 64 bit environments. Which it is can be determined, for example with dumpbin.exe /headers xyz.dll. Because its output is rather noisy, the output might be filtered with findstr:

C:\> dumpbin /headers xyz.dll | findstr /c:"machine (x"
C:\> dumpbin /headers xyz.exe | findstr /c:"machine (x"

If the output is something like 14C machine (x86), the Portable Executable was compiled for 32-bit, if it is something like 8664 machine (x64), it was compiled for 64-bit.