How to tell my Mac is running 64 or 32bit OS X?

I’m getting a question asking whether I’m running a 32 or 64 bit Snow Leopard? Here comes the solution.

  1. Go to the Apple menu,  click “About This Mac”
  2. Click “More Info” to learn more about your mac
  3. The System Profiler app is execute
  4. On the sidebar, click “Software”
  5. You will see 64-bit Kernel and Extensions, either it is Yes (you are running 64bit) or No (you are not).