Humpback whales are a large species and they do not disapont. The adult humpback whale can measure 45-50 feet (14-15 meters) in length with females being a litle longer then males, 3-6 feet (1-1.5 meters) Some females can even reach 60 feet (18 meters). Humpback whales are also very impressive in weight the average humpback whale is around 25-35 tons with the maximum weight being around 40-45 tons.