How does wire gauge correlate to thickness?

Have you ever wondered why 12 gauge wire is larger in diameter than 16 gauge?  It doesn't seem very clear until you think about how wire is drawn.

Wire is formed by pulling rod steel through a series of dies that continue to get smaller and smaller.  

As the wire is drawn through die one it is label “number 1”, then “2”, “3”, and so on as smaller wires are crafted.  The smaller the wire, the more times it was drawn, and with each drawing the number increases. 16 gauge wire is drawn more times than 12 gauge.

  This principle continued with time as gauge and  dies sizes were standardized, although now with  the  use of modern tools wire is often referred  to  as   its actual diameter.

Electricity moves down the external surface of the wire (conductor), the thicker the wire the larger the surface area.  The more surface area a wire has, the great its conductivity. 12 ½ gauge is always a good choice when building fences, because the diameter creates high conductivity and terrific visibility.