The Chihuahua weight chart is a great tool for estimating the adult weight of a Chihuahua puppy within a quarter pound. Keep in mind there are multiple factors which can affect the mature weight of your puppy such as genetics, food, and environment. Weight estimates become more accurate after a puppy reaches 8 weeks because young puppies are often over weight from their mother’s rich milk and lack of exercise. Around 4 weeks old, puppies become more stable and begin to run and play. Because of the added exercise, they usually begin to slim down to their optimal weight around 7-8 weeks old. At Sweetie Pie Pets, our method of determining Chihuahua weight estimates is to weigh them at 4 weeks, 5 weeks, 6 weeks, 7 weeks and 8 weeks old and chart their growth. If they remain in or near the same column then it’s an excellent indication they will stay on that growth curve for the remainder of their growing months. The table below is used as an estimating guide only. It is from a book called “The Complete Chihuahua Encyclopedia” by Hilary Harmar.