How big do American Mastiffs get?
Height at maturity is typically 32 to 36 inches for males. The average male weighs between 160 to over 200 pounds. Height at maturity for females is typically 28 to 34 inches. The average female weighs between 140 and 180 pounds. Larger or smaller for both males and females is acceptable provided the dog is in good proportion and structurally balanced.