The answer to this question depends on your needs. A California king has 4 inches of extra legroom than a king, making the California king size a better option for tall people. But area wise a king bed (6080 inches) is bigger than a California king bed (6048 inches). A king size mattress is 4 inches wider and 4 inches shorter than a Cal king. If you have more people sleeping on the bed, the wider king size is better for you.