What is the average weight of a mastiff?

On average, a healthy newborn Mastiff puppy may weigh anywhere between 13-22 ounces at birth. According to its size, the weight of the Mastiff male at 3 months should be between 22.9 and 30 kg. At 6 months, the Mastiff male weighs on average between 41.7 kg for the smallest individuals and 55 kg for the largest individuals.