A lot of times we get the question regarding the sizing of California King vs. King sized mattresses. Most people tend to think that California King mattresses are larger than King. However, this is not true. While a California King is slightly longer than a standard king mattress (also known as an “Eastern King”) it has less total surface area.
A California King is 72″ wide and 84″ long. It has a total surface area of 6,048 square inches.
A standard King sized mattress is 76″ wide and 80″ long. It has a total surface area of 6,080 square inches.
Note: In Canada, California King is not common, thus it's better to stick to the standard (Eastern) king as you will find bed frames, sheets, mattress protectors, .. etc much easier.