California king-size mattresses are more narrow and slightly longer than standard king-size mattresses. Despite having the same overall area, standard kings are 4 inches wider and 4 inches shorter than California kings.
California king beds are 72 inches wide and 84 inches long, while a standard king bed is 76 inches wide and 80 inches long. They are the two largest bed sizes, except for custom-made beds, available in the United States. As with all mattress purchases, choosing between the two depends on both the people sleeping in the bed and the size of the room.
Taller people would find more comfort in the California king, as its increased length accommodates longer frames, suggests About.com. However, because the bed is slightly narrower, it may not comfortably fit two adults. The standard king size is considered best for two people sharing the same bed because of its width. A standard king gives each person the same amount of sleeping space as a twin bed.
Before making a decision on either size, it is important to measure the room set aside for the bed. Allow a few extra inches for the frame and headboard. Take the measurements of the bed to make shopping for the correct size sheets easier. California king bed sheets don't fit well on standard king beds, and vice-versa.