The California king size mattress, also called a Western king, is the longest mattress that is commonly available. At 84 inches (213.4 cm) long, it is 4 inches (10.2 cm) longer than the Eastern king and is preferred by many people who are more than 6 feet (1.8 m) tall. Like an Eastern king, it typically comes with two twin box springs. For some people, the drawback of this mattress is that, at 72 inches (182.9 cm) wide, it is 4 inches (10.2 cm) more narrow than the Eastern king.
Shopping for a mattress can get a little confusing with all of the different sizes available. Aside from standard twin, twin long, double, full and queen beds, there are two types of king size mattresses that each have two different names. The difference between an Eastern king size mattress and a California King size mattress is that the California king is 4 inches (10.2 cm) longer and 4 inches (10.2 cm) narrower.