To estimate the mature weight of a Chihuahua using a weight chart, correspond the current weight of the dog as listed in the columns reading left to right, with its current age in the chart's rows reading top to bottom. Once you have found this number, follow the current column until you've reached the bottom of the chart to find the final estimated adult weight, explains PetChiDog.com.
The average Chihuahua reaches its final weight at about 18 months of age. AH Kennel warns, however, that factors such as genetics, bloodline and feeding regimen may affect a Chihuahua's weight. Because of this, it is best to have a Chihuahua weighed by a professional who is knowledgeable about the animal's guideline.
In addition, a Chihuahua's weight often fluctuates and plateaus as it grows. During the first eight weeks of life, the weight of the puppy may not be a reliable indicator of its weight as an adult. While the practice of weight estimation through the growth chart is an uncertain practice, Chihuahua Wardrobe notes that using the chart can eliminate a good deal of guesswork when purchasing collars, crates and other accessories. In addition, knowing a Chihuahua's future weight may help an owner in making choices for its general living environment.