what age do dogs become adults?
<answer> 12 and 16 months of age <context> Medium breeds, those weighing up to 80 pounds as adults, may reach their adult size between 12 and 16 months of age, according to the Cesar's Way website. Large and giant breeds, those over 80 pounds, may reach their full size between 18 months and 2 years old.If your puppy is still a youngling but you want to get an idea of what size he'll be as an adult, you can estimate his adult weight by doubling his weight at 4 months old, recommends PetEducation.com.arge and giant breeds, those over 80 pounds, may reach their full size between 18 months and 2 years old. If your puppy is still a youngling but you want to get an idea of what size he'll be as an adult, you can estimate his adult weight by doubling his weight at 4 months old, recommends PetEducation.com.