Who has a harder bite per square inch an American staphshire terrier or a mastiff?

The American Staffordshire Terrier has a bite force of approximately 235-250 PSI (pounds per square inch), while a Mastiff's bite force is generally around 556 PSI. Therefore, the Mastiff has a significantly harder bite per square inch compared to the American Staffordshire Terrier. This difference in bite force reflects their size and jaw structure.