According to Gotta Love a Lab, an average eight-week-old puppy should weigh about 5.9 to 6.35 Kilogram. "As the puppy gets older the accepted lab puppy weight is two pounds for each week of age." Using this formula, a four-month-old puppy should weigh 13.2 to 13.6 Kilogram.
Weight Is Determined by Gender and Breeding
According to the American Kennel Club, the average size of an adult Labrador retriever can range from 24.9 to 34 Kilogram. Males should weigh between 29.5 and 36.3 Kilogram, while females should weigh between 24.9 and 31.8 Kilogram. English Labradors typically weigh less than American Labs. Familiarity with your puppy's sire and dam can give you an indication of how large your puppy will be.
Use the formula of two pounds per week of age until the puppy is about 10 months old. Then consider your puppy's particular background--parents, type of Lab and age. Weigh your dog regularly, consult your veterinarian and take care not to overfeed your puppy or dog. Ribs should be easily felt through the coat but not noticeable. Labs are prone to hip dysplasia, a condition made worse when carrying excess weight, and Labrador retrievers are prone to overeating.