• Go to Facebook.com; find the person that you'd like to hack;
• Open his Facebook profile; Look at address bar on top of your browser;
• You will see something like this: http://www.facebook.com/user.name.profile
• Copy the whole URL above and go here to find the Facebook ID number.
• Magically, his Facebook ID number will appear on your screen.

Not working? - Try another way!

• If the Facebook ID number does not appear at method 1, follow those steps:
• Open his Facebook profile, click on his Facebook profile's photo.
• You will see a long URL on the address bar. Look at the end of the address.
• After the last dot [.] and before the [&type=1]
• ...369.XXXXXXXXXXXXXX&type=1
• XXXXXXXXXXXXXX is the Facebook ID you are looking for.

Not working? - Other method!