Depending on the size class and strain the dog belongs to, a rat terrier can grow up to 19 inches at the shoulder and weigh up to 40 pounds. The AKC breed standard for show dogs requires them to be under 18 inches in height to be exhibited.Know More
The largest rat terriers are of the Decker strain and are working dogs designed for farming and hunting. Deckers have been bred since the 1970s, although they aren't recognized by the AKC. The average rat terrier is 14 inches in height and weighs up to 25 pounds. The AKC divides the breed into standard and miniature classes, with miniatures growing to up to 13 inches in height.