Generate age

Hello,

I run http://www.young-perspective.net and I would like to display ages automatically in author bios, rather than having to manually update them when people turn x, y or z because sometimes we forget.

I was wondering if anyone out there new a little line of code (I am not someone who is very good at that) which can generate that. Our date of birth is simply called ‘dob’.

Basically what I assume I need to do is call ‘dob’ field call current date (not sure how you do that) and then minus dob from current date and display the answer.

Help much appreciated!