Many people wonder how big an American Bulldog is, well the truth is that there is a very large range in size for an adult male American Bulldog. American Bulldog size ranges from 65 pounds to 140 pounds. Females are slightly smaller than males. Typically it would be the standard type that is at the low end of the range but I have judged many very large standard american bulldogs in Germany. The real answer lies in the size of the parents so if you want a specific sized pet, look for parents in that range. The Classic type is mid range and the 100% Johnson American Bulldogs are at the high end of the range.