Breed standards for this dog do not generally specify a height, only a weight and a description of their overall proportions. As a result, height varies more than within many other breeds. Generally, the height ranges between six and ten inches; however, some dogs grow as tall as 12 to 15 inches (30 to 38 cm). Both British and American breed standards state that a Chihuahua must not weigh more than six pounds for conformation. However, the British standard also states that a weight of two to four pounds is preferred and that if two dogs are equally good in type, the more diminutive one is preferred. The Fédération Cynologique Internationale (FCI) standard calls for dogs ideally between 1.5 and 3.0 kg (3.3 to 6.6 lbs.), although smaller ones are acceptable in the show ring.[5] Pet-quality Chihuahuas (that is, those bred or purchased as companions rather than show dogs) often range above these weights, even above ten pounds if they have large bone structures or are allowed to become overweight. This does not mean that they are not purebred Chihuahuas; they do not meet the requirements to enter a conformation show. Oversized Chihuahuas are seen in some of the best, and worst, bloodlines. Typically the breed standard for both the long and short coat chihuahua will be identical except for the description of the coat.
Chihuahua breeders often use terms like Teacup, Pocket Size, Tiny Toy, Miniature or Standard to describe puppies. These terms are not recognized by the breed standards and are considered marketing gimmicks to inflate the value of puppies. Chihuahuas are commonly referred to as either Apple heads or Deer heads, the former having short noses and rounded heads similar to that of an apple; the latter having longer noses and more elongated heads.
from Wikipedia as of 8-8-2011
