There are a few things to know about a Split California King Mattress.  First, the size of the sleeping surface is divided into two, separate mattresses.  Each is 36” wide and 84” long, with a combined total sleep surface of 72” x 84” when set side by side.

The second thing to know is that a Split California King Mattress is sometimes referred to as a “Western King.”  It is called this due to its roots in the West Coast. As the size became more popular, especially with taller consumers, it shifted to being named Split California King.