A Labrador retriever puppy usually weighs about 1 pound when it is born and then gains about 2 pounds per week for the first six months of life. A Labrador puppy weighs between 11 and 17 pounds at 8 weeks old and then 50 to 60 pounds around six months before reaching a top weight of 65 to 80 pounds at 1 year old.

A study published in the Journal of Nutrition charted a Labrador puppy's growth from birth to 79 weeks. The puppy reached 20 pounds at 15 weeks after weighing half that at 8 weeks. The puppy steadily gained weight until it was 40 weeks old before leveling off at nearly 55 pounds. The dogs in the experiment were fed a normal diet of commercially available food designed for puppies. Weights were taken every week for the first 50 weeks of growth.

Labrador retrievers reach adult weight between 11 and 15 months of age. Male dogs are heavier than females by about 15 pounds. As puppies grow, they may seem clumsy because of their rapid weight gain. If a dog doesn't seem to be gaining weight properly as it grows, its owner should seek the advice of a veterinarian.