American alligators are 8 to 12 inches long at birth and grow 2 to 12 inches per year depending upon the habitat, food source and sex of the alligator. The size and age of the alligator affect alligators' growth as well, with older, larger alligators growing more slowly.
Male alligators grow up to 13 feet and more than 500 pounds, while females reach about 9 feet and around 200 pounds. In addition to growing larger than females, males grow faster, too. Large habitats with less competition for food increase growth rate and potential size. Alligators continue to grow throughout their lifetime.