Trucking: Trucking measurements, gcwr, gvwr

Question
Covered truck bed is 7ft wide, 12ft long, 6ft high.
What is the capacity or volume of the truck bed?

Answer
I assume you are referring to total GROSS weight of the truck LOADED? There is a manufacturers plate on the door jam that list that particular trucks GVWR or its GCWR. No matter what size the bed is: you have to be within that limit or you can and will get fined.