What is the difference between regular King (or Eastern King) and California King?
A regular King mattress is 78″ x 80″ while a California King is 72″ x 84″, i.e. narrower and longer. This mattress was something that the California mattress manufactures invented in order to make it more difficult for the big mattress companies in the East to compete. It has nothing to do with the fact that people may or may not be skinnier and taller in California.