The United Kennel Club, one of the leading authorities on dog breeds, considers the biggest American Pit Bull Terrier to weigh 60 pounds and to measure 21 inches tall at the shoulders. The club does not consider a dog larger than this to be a true American Pit Bull Terrier.
The United Kennel Club was founded in 1898 and registers dogs from the entire United States in addition to 25 foreign countries. It is the largest registry of its kind in the world. The club also provides a detailed reference page about the breed standards for American Pit Bull Terriers, including weight, height, and general characteristics.