Typically, a Labrador retriever weighs about a pound at birth but will weigh between 55 and 75 pounds when it reaches adulthood. How quickly a Labrador grows depends on several different factors like inherited genes, its diet and whether or not the dog has been spayed or neutered.
It is almost impossible to predict how fast a puppy will grow or which of his parents he will take after. Breeders will often try to predict the size of a puppy, especially for prospective owners who are looking for a dog that will grow to a particular size.
Labrador puppies will continue to grow until they are about a year old. At this time, upward growth will be complete, but the dog will continue to fill out by gaining muscle. Maturation is complete by the age of 2.
Often, dog owners will try to speed up or increase the size of their dogs by overfeeding. This is never recommended as it is possible for a puppy to grow too quickly, which causes problems with the joints and bones. Slow, steady growth is preferred and is overall better for the puppy.
Generally, by the age of 2, a Labrador retriever will weigh between 55 and 75 pounds, but each individual dog is different.