Originally from Mexico, Chihuahuas are classified as a "toy" dog and are the smallest known breed. Staying true to the toy classification, chihuahuas may range in size from 6 inches to 9 inches tall and may only get up to a weight of 6 lbs. Chihuahuas become fully grown when they are 18 months old. If you have a Chihuahua puppy, you can approximate how much it will weigh when it is an adult.
Weight yourself on a scale. If you can, weigh yourself on a scale that includes ounces, especially if you have a Chihuahua that is quite small. Write this number down.2
Hold the Chihuahua in your arms and step on the scale again. Write this number down.3
Subtract your weight from the weight of both you and the Chihuahua. This will be the approximate weight of the Chihuahua.4
Take the Chihuahua to the vet to get a more accurate weight reading. Write this number down.5
Look at a Chihuahua weight chart. The chart will give you an approximation of how much the dog will weigh when it is an adult. Refer to the Chihuahua Weight Chart on the Animal Haus Chihuahuas web site in the Resources section.6
Find how old your Chihuahua is on the weight chart. For example, if it is 7 weeks old, go down to the "7 weeks" option on the left-hand side.7
Look to the right of the age option and stop when you find how much your Chihuahua currently weighs. For example if your dog is 7 weeks old and weighs 22 oz., move from the 7-weeks option to the right until you find "22 oz." within the chart.8
Go down the column until you reach the bottom of the chart, where it will tell you how much your dog will weigh as an adult. For example, if your dog is 7 weeks old and weighs 22 oz., move down the column from "22 oz." to see that the Chihuahua will weigh 4.5 lbs. when it is fully grown.