Estimating just how big your adorable little puppy is going to be as an adult depends on a variety of factors including breed, nutrition, health and energy level. While you can get an estimate of how big your puppy will be from his age at 2 months, this is not a guarantee. This is especially true if your puppy is a mixed breed.
Begin by looking at your puppies parents. For purebred dogs, look at the adult weight of the dam and sire. This will give you a good idea as to how big your puppy will grow. If you do not have access to the parents of a purebred puppy, call a local breeder and ask about average adult weight.
If your puppy is a mixed breed, ask your veterinarian what breeds he believes your puppy is. If there is question as to the breeds, ask the vet if he would classify your puppy as a toy or small breed, medium or large breed or a giant breed. For some estimate calculations, the type of breed matters when choosing which age to use in the calculation.
Calculate the weight estimate by breed type. For toy and small breed dogs, take their weight at 6 weeks and double it. Take this number and double it again to receive your puppy’s estimated weight. For example, a Chihuahua that weighs 1 pound at 6 weeks would have an estimated adult weight of 4 pounds. For medium and larger breed dogs, take their weight at 14 weeks and double it. Then add half of the original weight. For example, your golden retriever puppy weighs 25 pounds at 14 weeks. Double this to 50 and then add 12.5 for an estimated adult weight of 62.5 pounds.
For another option, take your puppy’s weight and divide it by how many weeks old they are. Multiply the answer by 52. For example, if your puppy is 10 pounds at 2 months, or 8 weeks, divide 10 by 8 for an answer of 1.25. Multiply this number by 52 for a total adult weight estimate of 65 pounds.