I actually read somewhere that the ideal size for chis is 2-4 lbs, and that anything less than that is too little and too big isn't good either because obesity poses health problems, especially for chihuahuas. I know my baby will only be 3 1/2 according to the chart, but her mommy was 7 lbs. and her daddy was 6 lbs., so I have no idea. I heard that genetics, the amount of food you feed her, as well as other factors play a role in weight of your chihuahua. =)